big block head comparison

grumpyvette

Administrator
Staff member
Test 6: Edelbrock RPM Xtreme

The name Edelbrock has been around since the dawn of hot rodding, but it still has a few tricks up its collective sleeve. Case in point: Its RPM Xtreme heads, which offered the highest peak airflow of any of the heads we tested. Unfortunately, our test Rat, or more specifically our cam choice, was not able to capitalize on the available airflow, as it occurred at 0.700 lift, though the RPM Xtreme heads flowed nearly as much at 0.600 lift. These heads featured CNC porting through the intake, exhaust, and combustion chamber, and the power numbers reflected the extra work. Only the Edelbrock and AFR heads allowed the 468 to exceed 600 hp, as the Edelbrock-headed BBC produced 601 hp and 552 lb-ft of torque. The average power numbers also reflected the port work, with average horsepower and torque checking in at 498.2 hp and 524.1 lb-ft, respectively. Down at 4,000 rpm, the Edelbrock heads managed 514.9 lb-ft of torque and averaged over 515 lb-ft from 4,100 rpm to 6,100 rpm.

Notes: CNC porting throughout
Retail Price- $2,597 (porting customer-supplied castings)
Intake Valve Size-2.25
Exhaust Valve Size-1.88
Intake port vol-303 cc
Chamber Volume-111 cc
Peak Power-601 hp @ 6,200 rpm
Peak Torque-552 lb-ft @ 5,300 rpm
Avg HP [3,500-6,500]-498.2 hp
Avg TQ [3,500-6,500]-524.1 lb-ft
Tq @ 4,000 RPM-514.9 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 35 29
.100 63 61
.200 133 125
.300 210 186
.400 280 225
.500 327 257
.600 351 277
.700 353 285
 

grumpyvette

Administrator
Staff member
Test 7: Procomp Electronics

Procomp Electronics has made its name by providing affordable performance. Its BBC oval-port heads qualify on both counts, as the as-cast aluminum heads maximized airflow and minimized cost. The second of the true as-cast heads, the oval-ports from Procomp Electronics featured no porting or CNC chambers and instead relied on the as-cast port shape to maximize flow. With a peak flow number of 346 cfm, the Procomp Electronics casts had plenty of potential, but they were hampered by the largest combustion chamber of the group. The 121cc chambers dropped the static compression 1 full point compared to the other competitors. If each point is indeed worth an extra 3-4 percent in power, a comparable compression ratio would put these heads right in the hunt in terms of power. But equipped with the 121cc heads, the 468 produced 555 hp and 527 lb-ft of torque. Since compression hurts power everywhere, the average numbers dropped to 471.1 hp and 506.1 lb-ft of torque. Though down on power, Procomp Electronics should have no trouble selling these at a retail price of just over $1,000 a pair.

Notes: As cast, no porting
Retail Price- $1,095 (with spring upgrade)
Intake Valve Size-2.25
Exhaust Valve Size-1.88
Intake port vol-311 cc
Chamber Volume-121 cc
Peak Power-555 hp @ 6,200 rpm
Peak Torque-557 lb-ft @ 5,200 rpm
Avg HP [3,000-6,500]-471.1 hp
Avg TQ [3,000-6,500]-506.2 lb-ft
Tq @ 4,000 RPM-507.6 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 36 29
.100 77 61
.200 140 126
.300 214 174
.400 276 210
.500 314 241
.600 331 264
.700 346 284
 

grumpyvette

Administrator
Staff member
Test 8: Trick Flow Specialities 280
IVE USED THESE SEVERAL TIMES WITH GOOD RESULTS

http://users.erols.com/srweiss/tablehdc ... _Big_Block

When talk turns to performance cylinder heads, naturally Trick Flow Specialties has to be included. It stepped up for this test with a set of its PowerOval 280s. As indicated by the name, the PowerOvals combined 280cc intake ports with a 2.19/1.88 valve combination. Despite choosing the smaller intake valve (2.19 vs. 2.25), the PowerOval heads offered plenty of flow. Though the heads featured as-cast ports and chambers, the intake port did receive a minor port match. Even without the aide of CNC porting, the PowerOval heads offered flow numbers of 337 cfm on the intake and 261 cfm on the exhaust. These flow numbers translated into a peak power output of 576 hp and 544 lb-ft. The PowerOval heads offered a broad torque curve, bettering 515 lb-ft from 3,800 rpm to 5,700 rpm. In terms of average numbers, the TFS heads produced 485.7 hp and 521.7 lb-ft of torque and managed 517.8 lb-ft of torque at 4,000 rpm. The PowerOvals are affordably priced at under $2,000 assembled and ready to run.

Notes: As cast no ports and chambers
Retail Price- $1,849 (with spring upgrade)
Intake Valve Size-2.19
Exhaust Valve Size-1.88
Intake port vol-279 cc
Chamber Volume-113 cc
Peak Power-576 hp @ 6,100 rpm
Peak Torque-544 lb-ft @ 5,200 rpm
Avg HP [3,500-6,500]-485.7 hp
Avg TQ [3,500-6,500]-521.7 lb-ft
Tq @ 4,000 RPM-517.8 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 32 30
.100 67 62
.200 143 122
.300 212 160
.400 266 189
.500 302 221
.600 328 244
.700 337 261
 

grumpyvette

Administrator
Staff member
Dart Machinery
353 Oliver Street
Troy
MI 48084
248-362-1188
www.dartheads.com Brodix
301 Maple P.O. Box 1347
Mena
AR 71953
479-394-1075
www.brodix.com
Trick Flow Specialties
1248 Southeast Avenue
Tallmadge
OH 44278
330-630-1555
www.trickflow.com Holley/Hooker
1801 Russellville Road
Bowling Green
KY 42101
270-782-2900
www.holley.com
Comp Cams
3406 Democrat Road
Memphis
TN 38118
800-999-0853
www.compcams.com L&R Automotive
13731 Bora Drive
Sante Fe Springs
CA 90670
562-802-0443
www.lnrengine.com
Dr. J's Performance
436 S Montgomery Street
Orange
CA 92868
714-808-9780
www.j-performance.com Airflow Research
877-892-8844
www.airflowresearch.com
Edelbrock (Carbs)
800-416-8628
http://www.edelbrock.com Procomp Electronics
605 S. Milliken Avenue
Unit A
Ontario
CA 91761
909-605-1123
www.procompelectronics.com
 

grumpyvette

Administrator
Staff member
http://www.enginelabs.com/engine-tech/u ... nder-2000/
In general terms, big engines make big power! It stands to reason that if you want earth shaking, ground pounding power, you probably want to build a big block engine. Power, however, comes at a price. The old adage of “there’s no replacement for displacement” still holds true, but cubic inches of power doesn’t have to cost you cubic dollars. The high performance aftermarket has seen an influx of big block Chevy cylinder heads, many of which can fit into the tightest of budgets and still bring thundering punishment to the pavement.

When you are putting together the big block puzzle, one of the worse things you can do is buy whatever part is on sale this week. Randomly buying parts because they look good or because they have good street cred may cost you more in the long run. Big Block Chevy cylinder heads are a perfect example of where money spent wisely can pay off with some decent power without spending your kid’s entire college fund. Power does come at a price, but you can make some wise choices that produce the power you are expecting by picking up affordable heads.

With some smart shopping techniques, like knowing what your overall goal is, you can purchase a set of cylinder heads without breaking the bank, and more importantly, without compromising on power. To help answer the question of “What cylinder head do I need for my big block Chevy?”we have assembled a guide that will help you get through the dense jungle growth of BBC cylinder head choices. Follow along as we go for a run through the jungle.

The Key to Finding the Right Cylinder Head

RHS’ Product Manager Kevin Feeney summed up the process of finding the right set of heads for your BBC, “The first step is to determine what you are trying to accomplish with the engine. Are you looking for torque or horsepower, or the best combination of them both? This and the size of the engine are vital to choosing the proper runner sizes, valve sizes and ports for the application.”

With so many variables, and so many choices, it’s easy to go down the wrong path or find a shortcut to less performance. “Too many times guys tend to buy cylinder heads based on high lift flow numbers that are easily achieved with large ports and valves, but do not necessarily provide them with the performance they are looking for,” added Feeney.
What this Guide Covers

Our comprehensive guide to budget-friendly big block cylinder heads is strictly limited to fully configured and assembled units that are sold as a set for under $2,000 and are perfect for street use. We limited the spectrum of head choices to engines that are designed to run 91 octane pump gas and are not trailer queens. If you’re building a car that you can’t drive to the track, you’re probably not looking for a budget friendly set of cylinder heads anyway and this guide won’t cover the range of cylinder heads that you are looking for.

Our Criteria for budget friendly:

A fully configured and assembled set of cylinder heads
Priced under $2,000
Street or Street/Strip use
Designed to run on pump gas
Must be able to make more power than stock OEM cylinder heads

Factors To Consider

There are several factors to consider when selecting the right set of heads for your big block. Dart Machinery’s Advertising Director, Jack McInnis explained “The size of the engine, rpm range, camshaft, type of fuel, weight and gearing all factor in. Whether the car will be street driven 99% of the time, or if it will be primarily raced and driven on the street only occasionally will make a big difference in the choice as well.” Armed with McInnis’ warning to take a look at the whole picture, we have broken down some of the basic characteristics that you need to consider when selecting a budget big cube head.

Aluminum VS. Cast Iron

Cast iron is pretty common to most of us because it has been around the longest. Cast iron is inexpensive when compared to aluminum and is strong and durable. There are hundreds of different cast iron alloys but the kind that is typically used in cylinder heads is a gray cast iron. Gray cast iron is generally about 92-percent iron, 3.4 percent carbon, 2.5 percent silicon and 1.8 percent manganese. Rated at a tensile strength around 25,000 psi and a hardness somewhere near 180 on the Brinnell scale, cast iron heads are heavier than aluminum heads and can weigh as much as 30 percent more.

Aluminum’s main advantage is its light weight. Aluminum also dissipates heat very quickly, which may or may not be an advantage, depending on what you are trying to achieve. To make horsepower, you want some heat to be retained in the combustion chamber without detonation or preignition, which makes aluminum a great choice.

We talked to Billy Briggs of Briggs Performance about aluminum heads. “About the only drawback with aluminum is the simple fact that the aluminum alloy itself only has a life span of so long, but the pros are still huge. Ease of repair, ease of machining, heat dissipation and lighter weight are just a few,” said Briggs.

Aluminum alloys have become much better in recent years and the problems associated with heat warping aluminum heads in the early 1980s have been eliminated. There are some installation procedures that should be adhered to when installing aluminum cylinder heads for trouble free service.

Chad Golen of Golen Performance, a top notch GM LS engine builder, explained, “Aluminum has more expansion but doesn’t cause a problem with today’s head gaskets and high quality fasteners made by ARP. You just need to be careful bolting up accessories, like intakes and valve covers so you don’t damage the threads.”
 

grumpyvette

Administrator
Staff member
Another company that specializes in big block Chevy heads is Livernois Motorsports in Michigan. Mike Schropp, Engine Department Supervisor at Livernois, confirmed that, “While aluminum heads do contract and expand at different rates than the cast iron block they may be bolted to, most modern day gaskets, bolts and heads require little to no maintenance after being installed.”

The key is using good quality gaskets and hardware. “New style gaskets do an excellent job of allowing the two surfaces to scrub on each other and still maintain a seal,” said Schropp. Using the professional guidance from Golen and Schropp, we recommend budget builders to plan on buying good quality gaskets and hardware with an aluminum cylinder head. Schropp also suggested “using an anode rod to try and prevent corrosion of the aluminum surfaces from the dissimilar metals if you are using an aluminum head and a cast iron block.”

Closed or Open Combustion Chamber?

These terms get thrown around casually without consideration for what they purpose is behind the design of these chambers. In respect to big block Chevy heads, these terms relate to the size of the combustion chamber. An open chamber will have a larger combustion chamber; typically the valves are not shrouded and the engine breathes better. An open chamber can be identified by the dome area of the chamber extending to the diameter of the cylinder bore.

A closed chamber typically has a diameter much smaller than the cylinder bore. The smaller combustion chamber results in the block’s deck surface extending into the combustion chamber area which forces the air/fuel mixture into the smaller combustion chamber when the piston is on the compression stroke.

When the piston nears the cylinder head and the flat area of the piston top and the flat area of the cylinder head get close, the air/fuel mixture is “squished” into the combustion chamber closer to the spark plug. This is where the term “squish area” comes from. The space between the flat area of the piston top and the cylinder head typically run cooler than the rest of the chamber and piston. This lower temperature is where the term “quench area” comes from.

While the terms “quench” and “squish” are often used interchangeably by many manufacturers, quench and squish are not the same thing, nor are they produced by the same set of conditions. The Society of Automotive Engineers (SAE) has defined squish as the gases trapped between the piston dome and head that are ejected across the combustion chamber at high speed by the near-collision of the piston dome and head, causing turbulence and mixture homogenization. For our purposes, if the squish area is too close, there is a pumping loss and if the area is too far apart there will be lower squish velocity and less turbulence.

Quench on the other hand, is the ability to lower temperature of the end gases trapped between the piston dome and head by conduction. This prevents a second flame front from igniting the air/fuel mix prematurely. Members of the SAE acknowledge that for motors with 3.5” to 4.5” cylinder bores, a quench distance of 0.035” to 0.040” work well and result in near zero clearance due to thermal expansion, rod stretch and piston rock-over.

Properly designed quench areas have a dramatic effect on combustion quality and allow for higher compression ratios. For our budget friendly cylinder head guide, we can say in general terms, closed chambered heads can have an advantage in fuel efficiency and emissions by achieving a more complete burn, but valve shrouding can become an issue if the chamber is closed too much.

Combustion chamber size plays a significant role in compression (more is less and less is more). The smaller the combustion chamber, measured in cubic centimeters, the higher the compression will be.

Intake Port Shape and Size

It doesn’t take a lot of imagination to understand that a larger port has the potential to flow more than a smaller port. How much flow your engine needs will vary based on how much the engine can use. Port size is a very important issue when it comes to head design. Simply speaking in terms of flow, the smaller the port diameter, the less air potential there is.

Runner volume (length) is also very important. As the runner gets longer, movement in the column of air will increase the flow at lower RPMs and decrease the flow at higher RPMs.
 

grumpyvette

Administrator
Staff member
If you intend on doing a lot of low rpm street driving with a low-lift camshaft, performance will be less than optimal on cylinder heads with huge intake ports. The reverse is also true; high revving, big lift cammed engines with big displacement will not like smaller intake ports.

It’s true that a larger intake runner will allow more air and atomized fuel to flow through, but the larger area will also slow the velocity of the air and fuel flowing through it. Smaller runners speed up the flow, which improves throttle response and torque, but may not deliver the maximum amount of energy that your engine can use. The perfect combination of good flow and velocity is the challenge.

Common thought on port shapes is that oval shaped ports leave fewer opportunities for eddies and irregularities of flow in the corners because there are no corners, however, for budget friendly street heads running on pump gas, you should think of oval and rectangular ports as a function of size, not of shape.

RPMs are a big deal for street cars running on pump gas. Port shape is not as important as the cross sectional diameter and length of the runner matched to the RPMs. It’s highly unlikely that a street car is going to be spinning 7,000 RPM from stoplight to stoplight, thus a huge diameter, big volume oval port runner will probably under perform in the street RPM range.

Exhaust port shape and runner volume is even less important than the intake side, however, scavenging all the exhaust gasses from the combustion chamber means that you can refill the combustion chamber with more fuel and air. More fuel and air means more power, so there is some consideration in the exhaust runner size and exhaust port shape. Our best advice is to call the manufacturer’s tech lines or talk to your engine builder for guidance on runner size.

Comprehensive Guide to BBC Cylinder Heads by Application

For our guide, we chose to break down the “budget friendly” BBC cylinder heads into categories that include the entry level and work up to the street/strip category and up to the dedicated performance car level. We also include a breakdown on why we think the cylinder heads represented in each category are the best fit for the application. The cylinder heads are not listed in order of preference, simply by the company’s name in alphabetic order. Where applicable, we have included additional information on engine size as big block Chevy’s covered in this article range from engines manufactured from 1965 through 2006.

Budget Big Block Chevy Cylinder Heads For Entry Level Street

Looking for an entry level set of heads for street use goes beyond price. Given that GM factory production heads commonly had runner volumes of 230 to 270 cc. Larger volume runners were used in GM’s performance versions. Aftermarket cylinder heads have improved airflow but must be matched to the camshaft, intake and exhaust systems for the optimal results. The heads listed below are good choices for an application that is intended to be higher performing than stock and still used on the street for daily driving.

Smaller ports and runners will keep the mixture of air/fuel at a higher velocity making driving from stop light to stop light and idle quality a lot more steady. With too large of a runner volume, a basic stock type engine will lug at low RPMs until it gets to cruising speed. Entry level heads are designed for engine where there are not too many high performance upgrades already installed and the engine will be running on mid to high octane pump gas. Optimal runner volume for these conditions is
 

grumpyvette

Administrator
Staff member
Dart 308cc Big Block Chevy Heads, Rectangular Port

Dart 308 cast iron cylinder head.

Perfect for: Entry Level Street or Street/Strip where front end weight is not an issue.
Material: Cast Iron Alloy
Cost: $1,700 per set
Intake Runner: 308cc
Combustion Chamber: Heart Shaped, 121 cc

Additional Specs:
Part Number: 15100111
Intake Port Shape: Rectangular
Intake Runner Volume: 308cc
Exhaust Runner Volume: 129 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.660″
Springs Per Valve: Single
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Edelbrock E Street 290 (#50459)

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,725 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style, 110 cc

Additional Specs:
Part Number: 50459
Intake Port Shape: Oval
Intake Runner Volume: 290 cc
Exhaust Runner Volume: 110 cc
Exhaust Port Shape: D-Port
Intake Valve Diameter: 2.190″
Intake Valve Angle: 26°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 26°
Maximum Valve Lift: 0.700″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1963), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995)


Patriot Performance Freedom Series (#2211)

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,400 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary, 119 cc

Additional Specs:
Part Number 2211
Intake Port Shape: Rectangular
Intake Runner Volume: 320 cc
Exhaust Runner Volume: 125 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.600″
Springs Per Valve: hydraulic roller springs
Retainer Locks: 7°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Priced around $1,400 per set
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI
 

grumpyvette

Administrator
Staff member
Summit Racing Cast Iron (#SUM-152125)

Perfect for: Entry Level Street or Street/Strip
Material: Cast Iron
Cost: $1,500 per set
Intake Runner: 308cc
Combustion Chamber: Heart shaped 119 cc

Additional Specs:
Part Number: SUM-152125
Intake Port Shape: Rectangular
Intake Runner Volume: 308cc
Exhaust Runner Volume: 129 cc
Exhaust Port Shape: Square
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.660″
Springs Per Valve: Single
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995)


PowerOval 280

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,850 per set
Intake Runner: 280 cc
Combustion Chamber: Open Chamber 113 cc

Additional Specs:
Part Number: TFS-41300001 / TFS-41300002
Intake Port Shape: Oval
Exhaust Runner Volume: 137 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.190″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.700″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


World Products Merlin Oval Port Iron Heads

Perfect for: Entry Level Street or Street/Strip
Material: Cast Iron
Cost: $1,675 per set
Intake Runner: 269 cc
Combustion Chamber: Open Chamber 119 cc

World Products Merlin Oval Port Iron Heads.

Additional Specs:
Part Number: 030040-1 (Hydraulic Flat Tappet)/ 030040-2 (Solid Flat Tappet and Hydraulic Roller)
Intake Port Shape: Oval
Exhaust Port Shape: Round
Intake Valve Diameter: 2.300″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.600″
Springs Per Valve: 030040-1: Single. 030040-2: Dual
Retainer Locks: 7°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000
 

grumpyvette

Administrator
Staff member
Dart 345 cast iron cylinder heads

Perfect for: Street Performance
Material: Cast Iron
Cost: $1,800 per set
Intake Runner: 345 cc
Combustion Chamber: Heart Shaped 121 cc

Dart 345 cast iron cylinder head.

Additional Specs:
Part Number: 15200132
Intake Port Shape: Rectangular
Exhaust Runner Volume: 129 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.300″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.660″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


Edelbrock Performer 454-O

Perfect for: Street Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style 110 cc

Additional Specs:
Part Number: 60479
Intake Port Shape: Oval
Exhaust Runner Volume: 110 cc
Exhaust Port Shape: Square
Intake Valve Diameter: 2.190″
Intake Valve Angle: 26°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 26°
Maximum Valve Lift: 0.700″
Springs Per Valve: Single
Retainer Locks: 7°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


Patriot Performance Freedom Series (#2214)

Perfect for: Street Performance
Material: Aluminum
Cost: $1,600 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc

Additional Specs:
Part Number: 2214
Intake Port Shape: Rectangular
Exhaust Runner Volume: 125 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.700″
Springs Per Valve: dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
 

grumpyvette

Administrator
Staff member
RHS Pro Action 320 cc Hydraulic Roller

Perfect for: Street Performance
Material: Cast Iron
Cost: $1,575 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary Modified 119 cc

RHS Pro Action 320 Hydraulic Roller cast iron cylinder head.

Additional Specs:
Part Number: 11301-02
Intake Port Shape: Rectangular
Exhaust Runner Volume: 135 cc
Exhaust Port Shape: Rectangular
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.600″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


World Products Merlin Rectangular Port Iron Heads

Perfect for: Street Performance
Material: Cast Iron
Cost: $1,675
Intake Runner: 320 cc
Combustion Chamber: Open Chamber 119 cc

Additional Specs:
Part Number: 030620-2 (Solid Flat Tappet & Hydraulic Roller)/ 030620-3 (Solid Roller)
Intake Port Shape: Rectangular
Exhaust Port Shape: Round
Intake Valve Diameter: 2.300″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 030620-2: 0.650″ / 030620-3: 0.700″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


Wild Street and Dedicated Performance

For an application where performance is desired over streetability comfort. The heads listed below are for larger cubic inch big blocks where the airflow demands are greater or highway driving where the engine does not have to lumber through the gears to get to cruising speed often. Once you get to cruising speed however, these heads should provide all the flow you need or want.

Cylinder heads in the dedicated performance category will do well with intake and exhaust upgrades that maximize the flow characteristics. Large port openings and runner volumes along with larger valves and valve train set up for higher lift are the standards of a wild street or dedicated performance head.

Edelbrock High Compression 454-O (#60499) 50 state legal

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style 100 cc

Additional Specs:
Part Number: 60499
Intake Port Shape: Oval
Exhaust Runner Volume: 110 cc
Exhaust Port Shape: Square
Intake Valve Diameter: 2.190″
Intake Valve Angle: 26°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 26°
Maximum Valve Lift: 0.700″
Springs Per Valve: Single
Retainer Locks: 7°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


Trick Flow Specialties PowerPort 320

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,950 per set
Intake Runner: 320 cc
Combustion Chamber: Open Chamber 122 cc

Additional Specs:
Part Number: TFS-41400001 or TFS-41400002
Intake Port Shape: Rectangular
Exhaust Runner Volume: 137 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.700″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
 

grumpyvette

Administrator
Staff member
Patriot Performance Freedom Series (#2216)



Patriot Performance Freedom Series 2216 aluminum cylinder heads.

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc

Additional Specs:
Part Number: 2216
Intake Port Shape: Rectangular
Exhaust Runner Volume: 125 cc
Exhaust Port Shape: Round
Intake Valve Diameter: 2.300″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.800″
Springs Per Valve: Triple
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


RHS Pro Action 320 cc Solid Roller



RHS Pro Action 320 cc Solid Roller cast iron cylinder head.

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,780 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc

Additional Specs:
Part Number: 11301-03
Intake Port Shape: Rectangular
Exhaust Runner Volume: 135 cc
Exhaust Port Shape: Rectangular
Intake Valve Diameter: 2.250″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.750″
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


RHS Pro Action 360 cc

Perfect for: Wild Street Performance or Dedicated Performance
Material: Cast Iron
Cost: $1,780 per set
Intake Runner: 360 cc
Combustion Chamber: Proprietary 119 cc

Additional Specs:
Part Number: 11302-02 (Hydraulic Roller)or 11302-03 (Solid Roller)
Intake Port Shape: Rectangular
Exhaust Runner Volume: 135 cc
Exhaust Port Shape: Rectangular
Intake Valve Diameter: 2.300″
Intake Valve Angle: 24°
Exhaust Valve Diameter: 1.880″
Exhaust Valve Angle: 15°
Maximum Valve Lift: 0.600″ (11302-02) / 0.750″ (11302-03)
Springs Per Valve: Dual
Retainer Locks: 10°
Valve Train: Standard BBC 7/16” Stud Mount
Guideplates: Hardened Steel, 3/8″ Pushrod size
Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)


The Final Word

It’s been said that the terms “budget” and “big block” don’t go together and qualify as an oxymoron when used together. However, the cylinder heads listed in our guide above are well within the range of what can be considered budget friendly. Nan Gelhard of Summit Racing Equipment emphasized that point by saying; “When you talk about dollars per horsepower you can see how it changes as you go from street to strip.”

Whether you have a stock big block that you salvaged from the wrecking yard and are looking for some modern technology heads to bolt on, or if you want to beef up your daily driver to take it to the drag strip occasionally, we’ve got you covered in one of the budget friendly categories listed above.

Billy Mitchell Jr. from World Products encourages enthusiasts to call the tech lines or work with your engine builder. “It’s important to marry the runner size and port shape to the cubic inch size of the engine,” says Mitchell. Chad Bowling of Patriot Performance also recommended working with your engine builder on the engine internals like camshaft before picking a set of assembled heads, “Most aftermarket head manufacturers offer cylinder heads in a variety of spring packages from hydraulic flat tappet to solid roller,” Bowling states. The final word is that it is OK to use this guide as you would any other guide, as a means of gathering information to talk with your engine builder about the best method of achieving your goals.


Dart Machinery
Phone: 248-362-1188
Edelbrock
Phone: 310-781-2222
Patriot Performance
Phone: 888-462-8276
RHS
Phone: 877-776-4323
Summit Racing
Phone: 330-630-0240
Trick Flow Specialties
Phone: 330-630-1555
World Products
Phone: 631-981-1918
 

grumpyvette

Administrator
Staff member
http://www.airflowresearch.com/articles ... lnator.php

http://www.airflowresearch.com/articles ... o/oval.php

http://www.airflowresearch.com/articles ... ecoval.php

http://www.airflowresearch.com/articles ... ootout.php

worth watching, just for the tips on new head inspection

“Quality means doing it right when no one is looking.”

Henry Ford

“Quality is like buying oats. If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse ... that comes a little cheaper.”

an hour to a week spent in careful research,
before you buy or install parts,
can save you months or frustration
and easily 300%-to 500% of the eventually,
cost incurred in buying cheaper parts,in this hobby!



good quality parts tend to cost more, so expect to pay a fair price, remember the sweetness of low price tends to be forgotten long before the bitterness of living with low quality, that remains forever!

“It is quality rather than quantity that matters.

Seneca
“There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply. The person who buys on price alone is this man's lawful prey.”
John Ruskin

"the quality of a man's life is in direct proportion to his commitment to excellence, regardless of his chosen field of endeavor".

IN almost 100% of engine builds, your FAR better off purchasing and correctly installing a few high quality components, than you would be, after spending twice too three times as much money on, three to four times as many low quality parts randomly selected mostly because they were on sale!

GREAT DEALS!...RARELY ARE, looking back later!

0704ch_17_z+chevy_big_block.jpg

mark iv blocks
mrkiv.jpg

mark v blocks
markv.jpg

(keep in mind that ALL '91 and later Gen.V and Gen.VI big blocks come with 4-bolt main caps. The two-bolt big blocks are no longer in production
MANY BUT NOT ALL aftermarket head designs have been modified to work on both the early MARK IV 1965-90 and later MARK V & VI blocks 1991-later.)

BTW, , on BIG BLOCKS the oil pumps and oil filter adapters are different due to the block oil filter recess and rear seals being different
GEN 4 or MARK IV
bbcmk4.jpg


GEN V and VI
bbcmkv.jpg

A FEW RATHER INTERESTING BBC LINKS

http://www.ebay.com/itm/Chevy-BBC-396-4 ... 1203715393
KMJ BBC345124C
 
Last edited by a moderator:

grumpyvette

Administrator
Staff member
http://www.cartechbooks.com/techtips/ki ... lockchevy/
by Tom Dufur

The big-block Chevy’s canted valve heads are largely responsible for the tremendous power capability of the Rat motor and its continued popularity. The original head design is often referred to as having a 26-degree valve angle, although this intake valve angle of inclination is only one of four angles needed to numerically describe the big-block’s valve angles. The exhaust is tilted 17 degrees relative to the deck surface, and both are inclined 4 degrees laterally. This compound arrangement of valve angles gives the big-block head its characteristic “valves pointing everywhere” appearance when the valve covers are removed and is responsible for the early “porcupine head” nickname when the big-block made its debut in the mid 1960s.

aftermarketcylinderheadAluminum aftermarket cylinder heads offer tremendous airflow potential to maximize power potential.

Big-block Chevy factory heads are offered in aluminum and cast iron, with either open or closed combustion chambers, and with oval or rectangular intake ports. In the aftermarket, most performance heads are aluminum rectangular port, open-chamber designs reminiscent of the original LS6 casting, although you can also buy aftermarket oval port and cast-iron heads.

Factory heads are classified as either high-performance (rectangular port) or standard passenger car (oval ports). Late-model trucks feature an even smaller oval intake port, frequently referred to as the “peanut” port, on heads that appear to be nearly round at the port entrance. Rat motor heads feature a unique combination of siamesed intake ports mated with symmetrical combustion chambers and equally spaced exhaust ports.

As a result of this arrangement, each siamesed pair of intake runners features non-symmetrical left-hand and right-hand ports. The port on the right side of each pair (as you face the intake flange surface) is longer and directs the inlet charge more to the center of the chamber, and is referred to as the “good” port; the one of the left, obviously referred to as the “bad” port, dumps the air/fuel mix toward the cylinder wall and usually doesn’t flow as well as the right port. This minor idiosyncrasy of the big-block’s design has never been a real problem in terms of limiting the engine’s power potential, until extremely high airflow levels are reached on large-displacement or very-high-RPM engines. On engines approaching or exceeding the 1,000-hp mark (normally aspirated), the use of race-only spread port or Big Chief–style heads serves to even out the port volume, shape, and airflow in all eight intake ports.

Why didn’t the Chevrolet engineers just make it a mirror-image design like the small-block V-8? Because the big-block has six head bolts around each bore (if you count the hidden bolt bosses on the bottom of two of the intake ports), and that dictates where the intake ports must be placed. Also, it’s possible that the resulting siamesed exhaust ports might run too hot for long-term reliability with the big-block’s higher power levels and resulting increased exhaust flow.

Oval or Rectangular Intake Ports

Much has been said about the differences between rectangular ports and oval ports, and the only fact that everyone agrees with is that each design has its own strengths and weaknesses. All factory high-performance engines featured the larger rectangular port heads, which have higher airflow rates than production oval port heads. However, the larger volume of the rectangular ports produces rather sluggish flow velocities at low speeds, and smaller oval port heads are often a better choice for a daily driver or street and strip car.

bbcfg1.jpg


bbcfg2.jpg

5827.jpg

5828.jpg

Stock iron oval ports from a “206” casting head. Note Stock iron rectangular ports from a “990” casting head. distance from the ports to the center bolt-hole above Note that the tops of the ports are almost even with the the pair of runners. bottom of the center bolt-hole.

When reworked by someone who really knows what to do, oval port heads are capable of providing very good performance up to 600 or more horsepower. However, most high-performance street and full-race big-blocks can still take advantage of larger rectangular port heads. When I refer to the port size as larger or smaller, I’d like to think in terms of port cross-sectional area, but that dimension changes constantly throughout the length of the port, so the most common way to measure port size is to determine the volume in cubic centimeters, just as with the combustion chamber.

bolttorquepatternBig-block head bolt torque pattern. Stock head bolts get torqued to 70 ft-lbs in three steps of 40, 55, and 70 ft-lbs. Use thread sealer on all bolts that go into the water jacket, which means all blocks except Bowtie and aftermarket. Aftermarket studs usually get torqued to 60 ft-lbs, but check with the fastener manufacturer for specific torque recommendations.

While intake port volumes are a valuable guide in cylinder head selection, remember that port volume is not necessarily proportional to port flow, and that just because one design has 340-cc runners and another has 320s, that doesn’t mean that the larger head flows more air or makes more power, although that is usually the case.

In fact, if two heads with different- size runners have the same flowbench numbers, you are generally better off with the smaller runner head, especially if low-RPM throttle response and drivability are important. Also, when comparing port volume of spread port cylinder heads, remember that because these heads have raised runner locations, they are longer than conventional cylinder head intake ports, and the port volume is greater due to the extra length. A 400-cc raised-runner intake port may actually be smaller in cross-sectional area than a 380-cc conventional intake port. Be careful when comparing apples to oranges.

There are aftermarket oval port heads with about 290-cc intake runners, and small rectangular port heads with around 300-cc ports. I’ll bet you a year’s supply of donuts that the power difference on the dyno is minimal, and you could never tell the difference from the driver’s seat.
head bolts that show any thread damage should be replaced,
and be aware that NEW ARP studs put far less sress on threads,and are potentially stronger, than using bolts to secure heads to the block

Bolthelicoilrp.jpg

bbcgasketma.png


There are gaskets made specifically for this swap. Use other gaskets at you're own risk- these are what you want (from a V/R press release, presumably prior to the Gen 6 engine release):

General Motors 7.4L Head Gasket
Issue:

General Motors (GM) 7.4L (454 CID) engines use two types of engine blocks: the Mark IV and Mark V. The Mark IV is found on 7.4L engines in model years from 1965 to 1990, and the Mark V is found on 7.4L engines in model years from 1991 and newer.

Often, installers will attempt to adapt a Mark IVcylinder head for a Mark V block. This conversion can be made if attention is paid to the coolant circulation. Mark IV and Mark V have different coolant flows and were originally designed for different head gaskets. If the conversion is not performed correctly, the engine will overheat, causing premature engine wear and damage.

Resolution:
Victor Reinz has designed two Nitroseal® head gaskets to specifically allow for this conversion. The installation requires Victor Reinz part number 4918 be installed on the right cylinder bank to maintain proper coolant circulation, and part number 4923 to be installed on the left cylinder bank for the correct coolant flow.

Application:
Victor Reinz part numbers 4918(right bank) and 4923 (left bank) are available for GM 7.4L (454 CID)
engines.

bbcfg3.jpg
bbcfg4.jpg

Cast-iron late-1960s “206” head with bathtub-shaped Cast-iron high-performance rectangular port “990” head
98-cc closed combustion chambers with open 118-cc combustion chambers. Note the lazy-D
shape of the chambers.
BlackoutSteve posted these pictures
What cylinder head?
With my 4.280" bore and AFR head, I am forced to use a 4.540" bore gasket because the chambers are wide and would otherwise allow the gasket to "hang" in the chamber.

For example..
428gaga.jpg

454gaga.jpg
Big-block heads all had closed combustion chambers, or bathtub-shaped chambers, when the engine was introduced in the mid 1960s. In 1969 the open combustion chamber was introduced and it offered better air/fuel flow and a better combustion burn in the chamber. The only drawback to the new chamber design was that it was large, around 118 cc compared to closed chamber heads, which had about 101 to 109 cc, so high-dome pistons were needed to achieve the same compression ratios as the closed chamber heads. Note that domed pistons designed for open chamber cylinder heads do not work with closed chamber heads due to insufficient clearance. While introduced on high-performance rectangular port heads, the open combustion chamber was soon being used in common oval port heads to lower the compression ratio for use with unleaded gasoline, and the reduced quench area was found to be helpful in reducing exhaust emissions.

bbcfg5.jpg

before you spend a good deal of money porting and un-shrouding any iron cylinder heads, keep in mind aluminum heads are easily repaired in a skilled and experienced automotive machine shop thats equipped to do those repairs but damaged iron cylinder heads are either much harder to repair or good door stops
http://garage.grumpysperformance.com/index.php?threads/iron-vs-aluminum-heads.389/#post-7266

bbcfg6.jpg

Mark IV, Gen V and Gen VI Heads

All production big-block heads have similar characteristics, including 7/16-inch rocker studs (except Gen V and Gen VI) and the same seven-bolt valve cover pattern. Early cast-iron and all-aluminum heads used 3/4-inch-reach gasketed spark plugs, while most 1970-and-later iron heads switched to the smaller taper seat “peanut” plugs. Aluminum heads have two additional threaded bosses under the intake runners for additional clamping and better head gasket retention when used with engine blocks equipped with corresponding bosses in the lifter valley. The only OEM blocks with these bosses were the rare ZL1 aluminum blocks, but many modern aftermarket blocks have this added feature. Mark IV, Gen V and Gen VI heads all have the same head bolt pattern, but they are not interchangeable due to different water jacket cooling passages. Most aftermarket aluminum heads feature a universal water passage design allowing their use on Mark IV or Gen V/VI blocks, but you need to check with the manufacturer to verify this feature.

Gen V and Gen VI heads have different water jacket passages than Mark IV heads, and do not work on Mark IV blocks. (Photo Courtesy GMPP).
bbcfg7.jpg

All production big-block heads have stamped steel pushrod guideplates under the rocker arm studs for either 5/16-, 3/8-, or 7/16-inch pushrods, but Gen V/VI heads switched to a non-adjustable valvetrain. Although Gen V/VI heads retained the original valve cover bolt pattern, their matching cast aluminum valve covers were equipped with a durable rubber O-ring in place of the traditional valve cover gasket. All production heads use the same intake and exhaust bolt patterns, which include a bolt-hole between each pair of intake ports. The boss required for this additional bolt-hole intrudes on the port entrance, so it is deleted on most aftermarket heads because it is not necessary for a good gasket seal.
bbcfg8.jpg

All production big-block heads had an exhaust crossover passage between the two pairs of siamesed intake ports. The casting cavities above and below the center exhaust crossover are blind cavities that don’t connect to anything. Some aftermarket intake manifolds don’t cover the upper opening, which does not cause any problems.
heads2.jpg


peanutport.jpg

ovalvsreca.jpg


rectangle port heads generally work best on 500 or larger displacement engines
with at least 10:1 compression and cams with at least 245 duration at .050 lift and valve lifts over .600 to take advantage of the potential port flow rates


bbcr1port.jpg

bbcrport.jpg

bbcoport1.jpg

bbcoport.png

ovalrecgask.jpg


peanutportsiz.jpg


RELATED THREADS YOU SHOULD READ
http://garage.grumpysperformance.co...-peanut-port-big-block-combo.2900/#post-61085

http://garage.grumpysperformance.com/index.php?threads/porting-can-help.462/page-3#post-59145

http://garage.grumpysperformance.com/index.php?

http://garage.grumpysperformance.co...gine-build-up-for-the-street.3153/#post-11626

http://garage.grumpysperformance.co...tting-up-the-valve-train.181/page-2#post-7684

http://garage.grumpysperformance.co...a-peanut-port-big-block-combo.2900/#post-7532

http://garage.grumpysperformance.com/index.php?threads/cheaper-454-chevy-build.4620/#post-46849

http://garage.grumpysperformance.co...at-angles-and-air-flow.8460/page-2#post-32923

http://garage.grumpysperformance.co...olishing-combustion-chambers.2630/#post-50247

http://garage.grumpysperformance.com/index.php?threads/bbc-intake-manifold-choices.12949/

http://garage.grumpysperformance.co...ing-parts-and-a-logical-plan.7722/#post-57946

http://garage.grumpysperformance.com/index.php?threads/multi-angle-valve-job-related.3143/
look at the picture above the rectangle port gasket swallows the peanut port head port size but you can easily see the old sealant on the head surface where a previous standard oval port gasket was used
All OEM big-block heads had an exhaust crossover passage for intake manifold heat and automatic choke operation, as well as supplying exhaust gas for EGR-equipped (exhaust gas recirculation) vehicles from the early 1970s on. High-performance engine builders try to keep the intake manifold as cool as possible for maximum intake charge density, so performance intake gasket sets usually include metal plates to block off this exhaust crossover passage, and most aftermarket heads delete the exhaust crossover provision entirely.

All OEM Rat motor heads were equipped with steel valves that have 3/8-inch diameter valvestems, and the overall length of the intake valves is 5.218 inches while the exhaust valves measure 5.350 inches. Aftermarket heads typically come with 11/32-inch-diameter valvestems, and frequently use longer than stock valve lengths that allow installation of taller valvesprings that are better suited for use with high-lift camshafts. The smaller-diameter stems not only lighten the valves for better high-RPM performance, but also offer a slight improvement in airflow. OEM intake valve head diameters were either 2.06 or 2.19 inches, and exhaust valve heads measured either 1.72, 1.84, or 1.88 inches. All production heads and most aftermarket heads come with traditional 45-degree valve seats; however, some high-end aftermarket heads are available with 55-degree seats, which offer improved high-lift flow at the expense of some low-lift flow.

Aftermarket Cylinder Heads
bbcfg9.jpg


The vast majority of aftermarket heads are rectangular port aluminum with open combustion chambers, similar to the fabled LS6/LS7 production heads. However, they are much more than mere copies of the Chevy part, and many offer such advanced features as non-stock valve angles, larger valve head diameters for more flow, more robust valvesprings for high-RPM operation, and your choice of various intake port sizes to match your requirements. Some offer raised ports, usually by .100 inch on the intake ports and as much as 3/4 inch on the exhaust ports.

Many aftermarket heads, such as this Edelbrock Performer RPM 454-R, are rectangular port aluminum with open combustion chambers, similar to the fabled LS6/LS7 production heads. (Photo Courtesy Edelbrock)

Note that if you plan to use exhaust headers designed for stock heads in a stock engine compartment, you need to check for possible header interference with raised port heads, or have custom headers made. Typical material specs call for the use of either A355 or A356 aluminum alloy, usually hardened to T-6 specs, and most offer beefier construction with thicker-than-stock deck surfaces and port walls, allowing additional modifications by knowledgeable cylinder head specialists.

In addition to GMPP, there are an abundance of manufacturers offering high-performance heads for the big-block Chevy including Air Flow Research (AFR), Brodix, Carl Foltz Engineering (CFE), Dart, Edelbrock, Pro-Filer, Racing Head Service (RHS), Raptor (Reher-Morrison Racing Engines), Sonny’s Racing Engines (SRE), Trick Flow Specialties (TFS), World Products, and probably more by the time you read this. Contact the manufacturer of your choice for more specific information before making your final head selection.

Modern competition heads usually have heart-shaped combustion chambers to minimize chamber volume and increase the quench area.
bbcfg10.jpg



http://www.hotrod.com/how-to/engine/ccr ... der-heads/

http://users.erols.com/srweiss/tablehdc ... _Big_Block

There seems to be some confusion about the different head types used on Chevy Rat motors. Some people think there are only "oval" or "rectangular" ports, and some people don't understand the deal with "open" vs. "closed" chamber heads. This article, taken from the book by Ed Staffel "How To Build Max Performance Chevy Rat Motors", should help to explain the differences.

Small Oval Port (i.e. "peanut" port) heads

"Mark IV, Gen V and Gen VI small oval port cast iron heads, commonly called "truck", "round" or "peanut" ports and made from 1976 on, make power and high torque at very low RPM's and are helpful when the motor is pulling heavy loads in trucks, trailers or RV's. The velocity of air/fuel mixture in these heads is very high at low engine speeds, however they run out of breath at RPMs above 5,000 and are not really suitable for street performance or race applications, although larger valves, bowl and other port work can improve the flow situation. Small oval port heads have intake valves that are 2.06" in size, with 1.72" exhaust valves. They have hardened valve seats. These heads can have closed or open chambers (small or large chambers respectively). Most are found on trucks including late models, but there were some full size passenger cars and station wagons in the mid-70s that could be ordered with a 454 and may have the small oval port heads."

Large Oval Port Heads

"Mark IV large oval port heads make their power over a broader and higher RPM range. They are found on cars and trucks from 1965 through 1990 and make excellent street performance heads. They can be used on bracket drag race motors, after bowl porting and installation of bigger valves, with great results because they make a large amount of torque and will breathe well to about 6500RPM. They come with 2.06" intake and 1.72" exhaust valves. They have closed or open combustion chambers, and depending on when they were made have either soft or hardened valve seats. The open chamber style castings will flow more air than the closed chamber designs. This is due mainly to less valve shrouding. The downside with open chamber heads is that you will have to run a dome top piston to get any level of compression ratio above 8.5:1.

A good starting place would be cast iron, large oval port, open chamber casting #'s '781', '049', '359' or '241'. In 1996, Chevy introduced an over the counter aluminum open chamber head with large oval ports. This is the first factory big block aluminum head with large oval ports. This head will fit and seal with Mark IV, Gen V and Gen VI blocks.

Rectangular Port Heads

"Rectangular or 'square' port cast iron and aluminum cylinder heads are strictly for high-performance use. Because the intake port dimensions are so large, air/fuel velocities are at a low speed in the ports until the RPM's of the motor get high. Then the power comes on like gangbusters. Applications include high performance street use and racing where large volumes of air and fuel are required at high RPMs. Square port heads came with larger 2.19" intake and 1.88" exhaust valves. Some early closed chamber heads had 1.84" or 1.72" exhaust valves. Open or closed chambers were available with soft or hard valve seats. Once again, the open chamber designs on production heads will flow more air than the closed chamber production variety. If your engine is going to operate in the 7,000+ RPM range or if you are building a large cubic inch race motor, then the rec. port heads will make the power you need, but at a higher RPM."

http://www.superchevy.com/how-to/project-cars/sucp-1208-big-block-heads-shootout-the-o-vs-r/

Big-Block Heads Shootout - The Big O Vs. The Big R
Oval ports and rectangular port heads
Richard Holdener Jul 18, 2012 1 Comment(s)
View Full Gallery
Two issues back, we subjected a 468-inch big-block Chevy to a variety of different oval-port cylinder heads, ranging from stock peanut-port-style heads to full CNC-ported versions (see “The Big O”). In that story, we attempted to dispel the myth that any powerful big-block combination must include rectangular-port cylinder heads. Equipped with the right oval-port heads, the 468 easily exceeded 600 hp on the engine dyno. Most of the oval-port heads tested in part 1 offered airflow that would support another 100 hp on the right combination.

Contrary to popular opinion, our combination was limiting the potential of the oval-port cylinder heads, not the other way around. It is true that all of the factory performance big-blocks sported rectangular-port heads back in the day, but much has changed since the first muscle car era. Not only does a good set of aftermarket oval-port heads outflow the factory rec-port stuff, it does so with reduced port volume. Big, lazy ports are ideally suited for neither performance nor street use, while smaller, efficient ports offer the best of both worlds. Nowhere was this more evident than in the fact that a couple of manufacturers chose to supply oval-port heads once again on this larger (and more powerful) 496 test engine.

Top Searches
  • News
  • Cars
  • Neon
  • Global West 65 Chevelle Autocross Run




A common stroker displacement, our 496 was the result of combining a 0.060-inch overbore with a 4.25-inch stroker crank. Our BBC rotating assembly came from the experts at Scat Enterprises. The BBC combination featured a 4340 forged steel crank combined with a set of matching 6.385-inch, I-beam rods. We chose a Scat crankshaft design specifically for our late-model, one-piece, four-bolt, Gen-6 block. The Scat crank and rods were combined with a set of forged pistons from JE. Offered as part of their SRP line up, the JE Pistons featured 18cc domes to produce a static compression ratio of 10.0:1 with typical 120cc combustion chambers.


The short-block was built not to maximize power production, but rather to demonstrate what is possible for street use in a performance driver. We wanted all of our testing to be run on pump gas, so we kept the static compression at a reasonable level. L&R Automotive was responsible for machining and balancing of the combination, while Total Seal came through with a set of performance rings to ensure proper sealing.

The displacement ensured that our 496 would be more powerful than the 468 used in part 1, but we hedged our bets with the installation of a wilder cam profile as well. Balancing the street/performance theme, we chose a small solid roller profile from Comp Cams. The 300BR-14 offered 0.652 lift, a 255/262 duration split and 114-degree LSA. To work in the Gen-6 block, the cam was teamed with a set of 0.300-tall solid roller lifters and a double roller timing chain.

Since the cam and timing chain were designed for a Gen-4 block, it was necessary to eliminate the factory cam retaining plate in favor of a traditional cam button. The swap also required the use of a custom front cover (PN217) from Comp Cams to provide the necessary room for the double-roller chain (factory Gen-6 covers must be run with a single-roller chain).

Finishing touches on the test mill included an Edelbrock Victor Jr. 454-R intake, a Holley 950 HP carb and SFI-approved, neutral damper from Procomp Electronics.

Prior to running the test engine, all of the heads were treated to flow bench testing to correlate the flow potential to the power gains. In truth, heads like the Brodix BB-3 Xtra O offered over 400 cfm--enough to support more than 800 hp. We were just scratching the surface or their potential with our 496 street/strip combination. After bench testing, we subjected the heads to port and chamber volume measurements. Since the compression ration is a function of the chamber volume, chamber size has a significant effect on the power curve (to the tune of 3-4 percent per point). Measurements indicated that our test heads varied greatly, from a low of 107cc to a high of 123cc. Bear this in mind when viewing the power numbers.

It is again worth mentioning that though this was originally to be a rec-port-only head test (to follow the oval-ports tested in part 1), some of the manufacturers supplied oval-port heads for this 496. Don't look down you noses at oval-port heads, as testing from both stories suggests that if anything, oval is the new square.



Test 1: Stock GM 088 Iron

Prior to running any of the aftermarket heads we had to establish a baseline by running the stockers. We chose a set of 088 castings that featured 316cc intake ports, 121cc exhaust ports and 123cc combustion chambers. The airflow data suggested that the stock iron heads would support over 650 hp, but on this 496, the heads managed to produce peak numbers of 630 hp at 6,600 rpm and 577 lb-ft of torque at 5,300 rpm. While 630 hp would make a serious street motor, we would see that the right head choice on this application would add nearly 100 hp to that total.




  • GM rectangular port castings
  • Retail Price-NA
  • Intake Valve Size-2.19
  • Exhaust Valve Size-1.88
  • Intake Port Vol-316 cc
  • Exhaust Port-121 cc
  • Chamber Volume-123 cc
  • Peak Power- 630 @ 6,600 rpm
  • Peak Torque- 577 lb-ft @ 5,300 rpm
  • Avg HP (3,500-6,500)-532.4
  • Avg TQ (3,500-6,500)- 560.5 lb-
  • TQ @ 4,000 RPM - 562.7lb-ft
Flow Data: CFM @ 28-ins
Stock 088
Lift In Ex
0.050 32 27
0.100 77 56
0.200 144 112
0.300 206 142
0.400 245 166
0.500 289 188
0.600 320 192
0.700 334 197
0.800 335 201




Test 2: Summit Racing Iron

Many would dismiss the iron heads simply for the weight savings, but don't count them out, especially when you consider the price and performance. These rectangular port iron heads from Summit Racing offered surprising bang for the buck. The Summit Racing head upgrade improved the power output of the 496 from 630 hp and 577 lb-ft to 688 hp and 607 lb-ft. This was all the more impressive considering the fact that the heads cost just $750 bucks each, assembled. Toss in the fact that the Summit heads flow only marginally better than the stock heads and share the same combustion chamber volume. If you are looking for iron heads on a budget, look no further than Summit Racing.




  • Retail Price-$749
  • Intake Valve Size-2.25
  • Exhaust Valve Size-1.88
  • Intake Port Vol-309 cc
  • Exhaust Port Vol-127 cc
  • Chamber Volume-122 cc
  • Peak Power- 688 hp @ 6,600 rpm
  • Peak Torque- 607 lb-ft @ 5,400 rpm
  • Ave HP (3,500-6,500)-555.5
  • Ave TQ (3,500-6,500)-582.1
  • TQ @ 4,000 RPM-563.3 lb-ft

Summit Racing Iron
Flow Data: CFM @ 28-ins
Lift In Ex
.050 34 34
.100 69 69
.200 146 109
.300 204 155
.400 264 192
.500 309 223
.600 340 246
.700 323 262
.800 330 273




Test 3: Procomp Electronics Rec-Port CNC

The aluminum heads from Procomp Electronics combined the largest port volume and (nearly) peak flow numbers with the lowest retail cost. The intake port volume measured a sizable 369cc, while the exhaust checked in at 157cc. This head configuration would be much more at home on a larger displacement, higher horsepower application, but how can you argue with aluminum BBC heads that flowed over 400 cfm for around $600? Equipped with the Procomp heads, the BBC stroker pumped out 690 hp and 600 lb-ft of torque. We suspect the large port volume and sizable combustion chamber hurt torque and power on this application, as many of the other heads featured smaller chambers and port volumes. We'd like to see this head strut its stuff on a high-compression 572, but for our 496, it was likely just too big.




  • Retail Price-$625
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-369 cc
  • Exhaust Port Vol-157 cc
  • Chamber Volume-123 cc
  • Peak Power- 690 hp @ 6,300 rpm
  • Peak Torque- 600 lb-ft @ 5,500 rpm
  • Ave HP (3,500-6,500)-554.2 hp
  • Ave TQ (3,500-6,500)- 581 lb-ft
  • Tq @ 4,000 RPM-568.3 lb-ft

Procomp Electronics BBC Rec-Port CNC
Flow Data: CFM @ 28-ins
Lift In Ex
.050 35 31
.100 70 67
.200 152 132
.300 234 175
.400 294 206
.500 336 231
.600 364 251
.700 389 267
.800 403 279




Test 4: Trick Flow Specialties PowerPort 360 Heads

Like the Procomp heads, the PowerPort 360s from Trick Flow Specialties were probably a tad on the big side for the 496. With intake ports that measured 357cc, the impressive PowerPorts would be more at home on a big-block exceeding 500 cubic inches. With peak intake flow numbers of 384 cfm, the heads we capable of supporting over 750 hp, but on our 496 manage 691 hp and 603 lb-ft of torque. The PowerPort heads shared the large (122cc) combustion chamber volume of the stock heads and came in at a cost-effective $1,229 (through Summit Racing).




  • Retail Price-$1229
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-357 cc
  • Exhaust Port Vol-134 cc
  • Chamber Volume-122 cc
  • Peak Power- 691 hp @ 6,400 rpm
  • Peak Torque- 603 lb-ft @ 5,400 rpm
  • Ave HP (3,500-6,500)-555.3
  • Ave TQ (3,500-6,500)- 581.9 lb-ft
  • TQ @ 4,000 RPM-562.3 lb-ft

Trick Flow Specialties PowerPort 360 head
Flow Data: CFM @ 28-ins
Lift In Ex
.050 35 30
.100 72 61
.200 148 125
.300 217 168
.400 275 198
.500 325 227
.600 360 246
.700 376 261
.800 384 273




Test 5: Brodix BB-3 Xtra 332

The new Brodix BB-3 Xtra 332 heads were not quite a rec-port head nor were they a conventional oval (or peanut) port head. They were somewhere in the middle, more like a rectangular-port with rounded corners. In truth, use of the 454-R (rec-port) intake may have hindered the power potential of the Brodix heads more than others due to the port mismatch. One thing for certain is that the Brodix heads topped all comers in terms of airflow with peak numbers of 409 cfm. Capable of supporting over 800 hp, our 496 produced 705 hp and 624 lb-ft of torque. We would love to port-match an intake to these heads in an attempt to translate all that airflow potential into power.




  • Retail Price-$1840
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-335 cc
  • Exhaust Port Vol-133 cc
  • Chamber Volume-115 cc
  • Peak Power- 705 hp @ 6,400 rpm
  • Peak Torque- 624 lb-ft @ 5,200 rpm
  • Ave HP (3,500-6,500)-574.6
  • Ave TQ (3,500-6,500)- 602.7 lb-ft
  • TQ @ 4,000 RPM-585.7 lb-ft
Brodix BB-3 Xtra 33
Flow Data: CFM @ 28-ins
Lift In Ex
.050 33 31
.100 66 69
.200 147 120
.300 211 173
.400 273 221
.500 333 256
.600 380 277
.700 409 286
.800 403 296




Test 6: Dart Pro 1 335

The Pro 1 name from Dart has always meant power and this test illustrates that the name still carries some weight. For our street/strip 496 BBC, Dart supplied a set of its CNC-ported 335 heads. With flow numbers that reached nearly 400 cfm, the Dart Pro 1s were another set of 800-hp heads in search of a motor. The Dart Pro 1 heads featured rolled valve angles and raised exhaust ports to improve flow and power, but remained compatible with stock accessories. Run on the dyno, the big-block produced 717 hp and 619 lb-ft of torque. Equipped with a smaller chamber shared by the AFR and Edelbrock heads, the Dart would likely be right in the hunt for maximum power.




  • Retail Price-$2021
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-303 cc
  • Exhaust Port Vol-137 cc
  • Chamber Volume-122 cc
  • Peak Power- 717 hp @ 6,500 rpm
  • Peak Torque- 619 lb-ft @ 5,600 rpm
  • Ave HP (3,500-6,500)-568.0
  • Ave TQ (3,500-6,500)-594.3 lb-ft
  • TQ @ 4,000 RPM-572.5 lb-ft

Dart Pro 1 335
Flow Data: CFM @ 28-ins
Lift In Ex
.050 34 29
.100 69 61
.200 148 125
.300 228 181
.400 294 219
.500 336 249
.600 376 271
.700 398 281
.800 399 289




Test 7: Edelbrock E-CNC 355

Edelbrock has stepped up in a big way recently with new performance offerings and these E-CNC 335 heads are a perfect example. Proudly made in the USA, the E-CNC heads offered plenty of flow, peaking at 391 cfm on the intake and 285 cfm on the exhaust. Sporting the smallest combustion chamber of the bunch at 107cc, the Edelbrock heads produced the highest static compression ratio. Naturally this helped power, allowing the E-CNC heads to produce 723 hp and 627 lb-ft of torque.




  • Retail Price-$1,630 (required spring upgrade)
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-353cc
  • Chamber Volume-107 cc
  • Exhaust Port Vol-135 cc
  • Peak Power- 723 hp @ 6,500 rpm
  • Peak Torque- 627 lb-ft @ 5,600 rpm
  • Ave HP (3,500-6,500)-573.5 hp
  • Ave TQ (3,500-6,500)- 599.9 lb-ft
  • TQ @ 4,000 RPM-574.0 lb-ft

Edelbrock E-CNC 355
Flow Data: CFM @ 28-ins
Lift In Ex
.050 33 29
.100 73 61
.200 148 132
.300 224 185
.400 283 226
.500 334 252
.600 364 270
.700 385 278
.800 381 285




Test 8 AFR Magnum 300 Oval

It takes more than just big flow numbers to make power, and these Airflow Research heads proved that. In fact, when asked to supply rec-port heads for this test, they opted to instead send over a set of oval-port heads. It new 300cc Magnum heads did not offer the highest peak flow numbers, topping out at 383 cfm (at .650 lift), but when combined with exceptional mid-lift flow and an efficient chamber design, the results were enough impressive. Power production is all about the combination of components working together and on this 496, the AFR Magnum 300 heads proved to be the optimum combination by producing 729 hp and 639 lb-ft of torque.




  • Retail Price-$1,559
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-300 cc
  • Exhaust Port Vol-123 cc
  • Chamber Volume-110 cc
  • Peak Power- 729 hp @ 6,500 rpm
  • Peak Torque- 639 lb-ft @ 5,400 rpm
  • Avg HP (3,500-6,500)-584.1
  • Avg TQ (3,500-6,500)-611.4 lb-ft
  • TQ @ 4,000 rpm-587.0 lb-ft

AFR Magnum 300 Oval
Flow Data: CFM @ 28-ins
Lift In Ex
.050 34 32
.100 74 62
.200 153 126
.300 233 198
.400 296 237
.500 345 263
.600 377 277
.700 371 288
.800 365 296


sucp_1208_14_oval_rectangular_port_heads_the_big_vs_r_.jpg
38/38
21 The combustion chamber of each cylinder head tested was measured.
 
Last edited by a moderator:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
http://www.wengines.com/BBCweingartner.html
When the Mark IV was installed in production vehicles for the first time in 1965, it carried the Turbo-Jet name on the air cleaner, displaced 396 cubic inches, and was rated at a maximum of 425 horsepower in the Corvettes.

Here’s a quick look at milestones in the big-block’s expanding and contracting history of displacement:

396 cid – introduced in 1965, with 4.094-in. x 3.760-in. bore and stroke (first production Mark IV engine).

427 cid – introduced in 1966, with 4.250-in. x 3.760-in. bore and stroke (aluminum versions used in COPO supercars).

366 cid – introduced in 1968, with 3.935-in. x 3.760-in. bore and stroke (tall-deck; used in truck applications).

402 cid – introduced in 1970, with 4.125-in. x 3.760-in. bore and stroke (advertised as 396 cid).

454 cid – introduced in 1970, with 4.250-in. x 4.000-in. bore and stroke.

502 cid – introduced in 1988, with 4.466-in. x 4.000-in. bore and stroke (Gen V block, originally developed for non-automotive applications; adapted later by Chevrolet Performance).

572 cid – introduced in 2003, with 4.560-in. x 4.375-in. bore and stroke (developed by Chevrolet Performance; no production vehicle applications).
 
Last edited:
8

87vette81big

Guest
Impressive at a glance skim reading Grumpy.

No way in hell would I start from scratch SBC & LSX.
Both limited & realized this year.

The Olds 425 is Super Rare today a BBC Guy told me not far from me.
Valuable to right guy.
$5 k Value possible . Also complete unlike most found.
Play with it for a while.
Resell.
Want to make You Tube Videos of '63 GP in action. Cleaning house on the street. 425 .
 

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
Ultimate Guide to Budget BBC Cylinder Heads Under $2,000 (WHENEAGLESFLY) posted this


http://www.felpro.com/technical/tecblogs/head-gasket-coolant-holes.html


bbchgk1.jpg


rectvsoval.jpg

the upper closed chamber head is bath tube shaped to provide dual opposed quench areas that squish against the piston deck,
forcing the fuel air mix toward the central cylinder bore, the lower open chamber head combustion chamber was found to un-shroud the valves,\
thus increasing the cylinder fill efficiency especially at upper rpms.
the dome higher compression ratio pistons for both combustion chambers are similar in shape to the combustion chambers they are designed too be used with.
the closed chamber piston can be used with the larger open chamber combustion chamber , but its reduced volume results in less effective compression and the dome,
of the closed chamber dome is marginally restrictive to the flame front propagation.

bbchead1.jpg

opench1.jpg

opench2.jpg





Report this image

In general terms, big engines make big power! It stands to reason that if you want earth shaking, ground pounding power, you probably want to build a big block engine. Power, however, comes at a price. The old adage of “there’s no replacement for displacement” still holds true, but cubic inches of power doesn’t have to cost you cubic dollars. The high performance aftermarket has seen an influx of big block Chevy cylinder heads, many of which can fit into the tightest of budgets and still bring thundering punishment to the pavement.
When you are putting together the big block puzzle, one of the worse things you can do is buy whatever part is on sale this week. Randomly buying parts because they look good or because they have good street cred may cost you more in the long run. Big Block Chevy cylinder heads are a perfect example of where money spent wisely can pay off with some decent power without spending your kid’s entire college fund. Power does come at a price, but you can make some wise choices that produce the power you are expecting by picking up affordable heads.
With some smart shopping techniques, like knowing what your overall goal is, you can purchase a set of cylinder heads without breaking the bank, and more importantly, without compromising on power. To help answer the question of “What cylinder head do I need for my big block Chevy?”we have assembled a guide that will help you get through the dense jungle growth of BBC cylinder head choices. Follow along as we go for a run through the jungle.
The Key to Finding the Right Cylinder Head
RHS’ Product Manager Kevin Feeney summed up the process of finding the right set of heads for your BBC, “The first step is to determine what you are trying to accomplish with the engine. Are you looking for torque or horsepower, or the best combination of them both? This and the size of the engine are vital to choosing the proper runner sizes, valve sizes and ports for the application.”
With so many variables, and so many choices, it’s easy to go down the wrong path or find a shortcut to less performance. “Too many times guys tend to buy cylinder heads based on high lift flow numbers that are easily achieved with large ports and valves, but do not necessarily provide them with the performance they are looking for,” added Feeney.
GrayIronFoundry.jpg

Report this image
Cast Iron being poured into molds at the foundry. (Photo from CFM Corporation)

What this Guide Covers
Our comprehensive guide to budget-friendly big block cylinder heads is strictly limited to fully configured and assembled units that are sold as a set for under $2,000 and are perfect for street use. We limited the spectrum of head choices to engines that are designed to run 91 octane pump gas and are not trailer queens. If you’re building a car that you can’t drive to the track, you’re probably not looking for a budget friendly set of cylinder heads anyway and this guide won’t cover the range of cylinder heads that you are looking for.
Our Criteria for budget friendly:
  • A fully configured and assembled set of cylinder heads
  • Priced under $2,000
  • Street or Street/Strip use
  • Designed to run on pump gas
  • Must be able to make more power than stock OEM cylinder heads
DSC_0244.jpg

Report this image
Take a look at the big picture before rushing out to buy the first set of BBC heads you see.

Factors To Consider
There are several factors to consider when selecting the right set of heads for your big block. Dart Machinery’s Advertising Director, Jack McInnis explained “The size of the engine, rpm range, camshaft, type of fuel, weight and gearing all factor in. Whether the car will be street driven 99% of the time, or if it will be primarily raced and driven on the street only occasionally will make a big difference in the choice as well.” Armed with McInnis’ warning to take a look at the whole picture, we have broken down some of the basic characteristics that you need to consider when selecting a budget big cube head.
ValveSpringsRetainers.jpg

Report this image
Aluminum heads look great and have a lot of good things going for them, but are they right for you?

Aluminum VS. Cast Iron
Cast iron is pretty common to most of us because it has been around the longest. Cast iron is inexpensive when compared to aluminum and is strong and durable. There are hundreds of different cast iron alloys but the kind that is typically used in cylinder heads is a gray cast iron. Gray cast iron is generally about 92-percent iron, 3.4 percent carbon, 2.5 percent silicon and 1.8 percent manganese. Rated at a tensile strength around 25,000 psi and a hardness somewhere near 180 on the Brinnell scale, cast iron heads are heavier than aluminum heads and can weigh as much as 30 percent more.
Aluminum’s main advantage is its light weight. Aluminum also dissipates heat very quickly, which may or may not be an advantage, depending on what you are trying to achieve. To make horsepower, you want some heat to be retained in the combustion chamber without detonation or preignition, which makes aluminum a great choice.
We talked to Billy Briggs of Briggs Performance about aluminum heads. “About the only drawback with aluminum is the simple fact that the aluminum alloy itself only has a life span of so long, but the pros are still huge. Ease of repair, ease of machining, heat dissipation and lighter weight are just a few,” said Briggs.
Aluminum alloys have become much better in recent years and the problems associated with heat warping aluminum heads in the early 1980s have been eliminated. There are some installation procedures that should be adhered to when installing aluminum cylinder heads for trouble free service.
Chad Golen of Golen Performance, a top notch GM LS engine builder, explained, “Aluminum has more expansion but doesn’t cause a problem with today’s head gaskets and high quality fasteners made by ARP. You just need to be careful bolting up accessories, like intakes and valve covers so you don’t damage the threads.”

Another company that specializes in big block Chevy heads is Livernois Motorsports in Michigan. Mike Schropp, Engine Department Supervisor at Livernois, confirmed that, “While aluminum heads do contract and expand at different rates than the cast iron block they may be bolted to, most modern day gaskets, bolts and heads require little to no maintenance after being installed.”
The key is using good quality gaskets and hardware. “New style gaskets do an excellent job of allowing the two surfaces to scrub on each other and still maintain a seal,” said Schropp. Using the professional guidance from Golen and Schropp, we recommend budget builders to plan on buying good quality gaskets and hardware with an aluminum cylinder head. Schropp also suggested “using an anode rod to try and prevent corrosion of the aluminum surfaces from the dissimilar metals if you are using an aluminum head and a cast iron block.”
combustionChamber1.jpg

Report this image
Combustion chamber design and volume are important in how the fuel is burnt.

Closed or Open Combustion Chamber?
These terms get thrown around casually without consideration for what they purpose is behind the design of these chambers. In respect to big block Chevy heads, these terms relate to the size of the combustion chamber. An open chamber will have a larger combustion chamber; typically the valves are not shrouded and the engine breathes better. An open chamber can be identified by the dome area of the chamber extending to the diameter of the cylinder bore.
A closed chamber typically has a diameter much smaller than the cylinder bore. The smaller combustion chamber results in the block’s deck surface extending into the combustion chamber area which forces the air/fuel mixture into the smaller combustion chamber when the piston is on the compression stroke.
When the piston nears the cylinder head and the flat area of the piston top and the flat area of the cylinder head get close, the air/fuel mixture is “squished” into the combustion chamber closer to the spark plug. This is where the term “squish area” comes from. The space between the flat area of the piston top and the cylinder head typically run cooler than the rest of the chamber and piston. This lower temperature is where the term “quench area” comes from.
combustionChamber.jpg

Report this image
Semi-open combustion chamber heads can flow extremely well and provide the right mix of turbulence and "squish".

While the terms “quench” and “squish” are often used interchangeably by many manufacturers, quench and squish are not the same thing, nor are they produced by the same set of conditions. The Society of Automotive Engineers (SAE) has defined squish as the gases trapped between the piston dome and head that are ejected across the combustion chamber at high speed by the near-collision of the piston dome and head, causing turbulence and mixture homogenization. For our purposes, if the squish area is too close, there is a pumping loss and if the area is too far apart there will be lower squish velocity and less turbulence.
Quench on the other hand, is the ability to lower temperature of the end gases trapped between the piston dome and head by conduction. This prevents a second flame front from igniting the air/fuel mix prematurely. Members of the SAE acknowledge that for motors with 3.5” to 4.5” cylinder bores, a quench distance of 0.035” to 0.040” work well and result in near zero clearance due to thermal expansion, rod stretch and piston rock-over.

Properly designed quench areas have a dramatic effect on combustion quality and allow for higher compression ratios. For our budget friendly cylinder head guide, we can say in general terms, closed chambered heads can have an advantage in fuel efficiency and emissions by achieving a more complete burn, but valve shrouding can become an issue if the chamber is closed too much.
Combustion chamber size plays a significant role in compression (more is less and less is more). The smaller the combustion chamber, measured in cubic centimeters, the higher the compression will be.
Intake Port Shape and Size
It doesn’t take a lot of imagination to understand that a larger port has the potential to flow more than a smaller port. How much flow your engine needs will vary based on how much the engine can use. Port size is a very important issue when it comes to head design. Simply speaking in terms of flow, the smaller the port diameter, the less air potential there is.
Runner volume (length) is also very important. As the runner gets longer, movement in the column of air will increase the flow at lower RPMs and decrease the flow at higher RPMs.
bbcPort.jpg

Report this image
Intake port shape and size are important considerations in reaching your goal.

If you intend on doing a lot of low rpm street driving with a low-lift camshaft, performance will be less than optimal on cylinder heads with huge intake ports. The reverse is also true; high revving, big lift cammed engines with big displacement will not like smaller intake ports.
It’s true that a larger intake runner will allow more air and atomized fuel to flow through, but the larger area will also slow the velocity of the air and fuel flowing through it. Smaller runners speed up the flow, which improves throttle response and torque, but may not deliver the maximum amount of energy that your engine can use. The perfect combination of good flow and velocity is the challenge.
Common thought on port shapes is that oval shaped ports leave fewer opportunities for eddies and irregularities of flow in the corners because there are no corners, however, for budget friendly street heads running on pump gas, you should think of oval and rectangular ports as a function of size, not of shape.
RPMs are a big deal for street cars running on pump gas. Port shape is not as important as the cross sectional diameter and length of the runner matched to the RPMs. It’s highly unlikely that a street car is going to be spinning 7,000 RPM from stoplight to stoplight, thus a huge diameter, big volume oval port runner will probably under perform in the street RPM range.
runner.jpg

Report this image
Runner volume can make or break a daily driver.

Exhaust port shape and runner volume is even less important than the intake side, however, scavenging all the exhaust gasses from the combustion chamber means that you can refill the combustion chamber with more fuel and air. More fuel and air means more power, so there is some consideration in the exhaust runner size and exhaust port shape. Our best advice is to call the manufacturer’s tech lines or talk to your engine builder for guidance on runner size.
Comprehensive Guide to BBC Cylinder Heads by Application
For our guide, we chose to break down the “budget friendly” BBC cylinder heads into categories that include the entry level and work up to the street/strip category and up to the dedicated performance car level. We also include a breakdown on why we think the cylinder heads represented in each category are the best fit for the application. The cylinder heads are not listed in order of preference, simply by the company’s name in alphabetic order. Where applicable, we have included additional information on engine size as big block Chevy’s covered in this article range from engines manufactured from 1965 through 2006.
Budget Big Block Chevy Cylinder Heads For Entry Level Street
Looking for an entry level set of heads for street use goes beyond price. Given that GM factory production heads commonly had runner volumes of 230 to 270 cc. Larger volume runners were used in GM’s performance versions. Aftermarket cylinder heads have improved airflow but must be matched to the camshaft, intake and exhaust systems for the optimal results. The heads listed below are good choices for an application that is intended to be higher performing than stock and still used on the street for daily driving.
Smaller ports and runners will keep the mixture of air/fuel at a higher velocity making driving from stop light to stop light and idle quality a lot more steady. With too large of a runner volume, a basic stock type engine will lug at low RPMs until it gets to cruising speed. Entry level heads are designed for engine where there are not too many high performance upgrades already installed and the engine will be running on mid to high octane pump gas. Optimal runner volume for these conditions is somewhere in the range of 270 cc to 290 cc.
Dart 308cc Big Block Chevy Heads, Rectangular Port
Dart-Iron-Eagle-400x193.jpg

Report this image
Dart 308 cast iron cylinder head.

Perfect for: Entry Level Street or Street/Strip where front end weight is not an issue.
Material: Cast Iron Alloy
Cost: $1,700 per set
Intake Runner: 308cc
Combustion Chamber: Heart Shaped, 121 cc
  • Additional Specs:
    • Part Number: 15100111
    • Intake Port Shape: Rectangular
    • Intake Runner Volume: 308cc
    • Exhaust Runner Volume: 129 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.660″
    • Springs Per Valve: Single
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
EDL-50459_EQ.jpg

Report this image
Edelbrock E Street 290 aluminum cylinder head.

Edelbrock E Street 290 (#50459)

Perfect for: Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,725 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style, 110 cc
  • Additional Specs:
    • Part Number: 50459
    • Intake Port Shape: Oval
    • Intake Runner Volume: 290 cc
    • Exhaust Runner Volume: 110 cc
    • Exhaust Port Shape: D-Port
    • Intake Valve Diameter: 2.190″
    • Intake Valve Angle: 26°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 26°
    • Maximum Valve Lift: 0.700″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1963), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995)
patriot-2211.jpg

Report this image
Patriot Performance Freedom Series 2211 aluminum cylinder head.

Patriot Performance Freedom Series (#2211)
Perfect for:
Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,400 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary, 119 cc
  • Additional Specs:
    • Part Number 2211
    • Intake Port Shape: Rectangular
    • Intake Runner Volume: 320 cc
    • Exhaust Runner Volume: 125 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.600″
    • Springs Per Valve: hydraulic roller springs
    • Retainer Locks: 7°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Priced around $1,400 per set
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
sum-152125_w.jpg

Report this image
Summit Racing cast iron cylinder head.

Summit Racing Cast Iron (#SUM-152125)
Perfect for: Entry Level Street or Street/Strip
Material: Cast Iron
Cost: $1,500 per set
Intake Runner: 308cc
Combustion Chamber:
Heart shaped 119 cc
  • Additional Specs:
    • Part Number: SUM-152125
    • Intake Port Shape: Rectangular
    • Intake Runner Volume: 308cc
    • Exhaust Runner Volume: 129 cc
    • Exhaust Port Shape: Square
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.660″
    • Springs Per Valve: Single
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995)
tfs-41300001.jpg

Report this image
Trick Flow Specialties PowerOval 280 aluminum cylinder heads.

Trick Flow Specialties PowerOval 280
Perfect for:
Entry Level Street or Street/Strip
Material: Aluminum
Cost: $1,850 per set
Intake Runner: 280 cc
Combustion Chamber: Open Chamber 113 cc
  • Additional Specs:
    • Part Number: TFS-41300001 / TFS-41300002
    • Intake Port Shape: Oval
    • Exhaust Runner Volume: 137 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.190″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.700″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
World Products Merlin Oval Port Iron Heads
Perfect for:
Entry Level Street or Street/Strip
Material: Cast Iron
Cost: $1,675 per set
Intake Runner: 269 cc
Combustion Chamber: Open Chamber 119 cc
world-030040-1.jpg

Report this image
World Products Merlin Oval Port Iron Heads.

  • Additional Specs:
    • Part Number: 030040-1 (Hydraulic Flat Tappet)/ 030040-2 (Solid Flat Tappet and Hydraulic Roller)
    • Intake Port Shape: Oval
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.300″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.600″
    • Springs Per Valve: 030040-1: Single. 030040-2: Dual
    • Retainer Locks: 7°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Street Performance & Muscle Car
Typically a bigger valve, port size and runner volume are desired in higher performance applications, however, knowing that this guide is for budget friendly, pump gas, street cruisers, we were looking for runner volumes in the range of 290 cc to 320 cc. On the smaller cubic inch big blocks, it’s probably still wise to stay down in the 290 cc to 305 cc range for drivability.
454 cubic inch big blocks are considered small by today’s standards where 502 ci and 572 ci engines are becoming more common. Obviously, a 454 ci engine will not have the same airflow demands as a 572 ci engine. The cylinder heads listed below still have good drivability in stop-and-go driving situations and low speed response while giving improved performance at the top end.
Dart 345 cast iron cylinder heads
Perfect for:
Street Performance
Material: Cast Iron
Cost: $1,800 per set
Intake Runner: 345 cc
Combustion Chamber: Heart Shaped 121 cc
Dart-Iron-Eagle1.jpg

Report this image
Dart 345 cast iron cylinder head.

  • Additional Specs:
    • Part Number: 15200132
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 129 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.300″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.660″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
EDL-60479.jpg

Report this image
Edelbrock Performer 454-O aluminum cylinder head.

Edelbrock Performer 454-O
Perfect for:
Street Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style 110 cc
  • Additional Specs:
    • Part Number: 60479
    • Intake Port Shape: Oval
    • Exhaust Runner Volume: 110 cc
    • Exhaust Port Shape: Square
    • Intake Valve Diameter: 2.190″
    • Intake Valve Angle: 26°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 26°
    • Maximum Valve Lift: 0.700″
    • Springs Per Valve: Single
    • Retainer Locks: 7°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
Patriot-2214.jpg

Report this image
Patriot Performance Freedom Series 2214 aluminum cylinder heads.

Patriot Performance Freedom Series (#2214)
Perfect for:
Street Performance
Material: Aluminum
Cost: $1,600 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc
  • Additional Specs:
    • Part Number: 2214
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 125 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.700″
    • Springs Per Valve: dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
RHS Pro Action 320 cc Hydraulic Roller
Perfect for:
Street Performance
Material: Cast Iron
Cost: $1,575 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary Modified 119 cc
RHS-11302-02.jpg

Report this image
RHS Pro Action 320 Hydraulic Roller cast iron cylinder head.

  • Additional Specs:
    • Part Number: 11301-02
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 135 cc
    • Exhaust Port Shape: Rectangular
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.600″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
world-030620-2.jpg

Report this image
World Products Merlin Rectangular Port Iron Heads.

World Products Merlin Rectangular Port Iron Heads
Perfect for:
Street Performance
Material: Cast Iron
Cost: $1,675
Intake Runner: 320 cc
Combustion Chamber: Open Chamber 119 cc
  • Additional Specs:
    • Part Number: 030620-2 (Solid Flat Tappet & Hydraulic Roller)/ 030620-3 (Solid Roller)
    • Intake Port Shape: Rectangular
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.300″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 030620-2: 0.650″ / 030620-3: 0.700″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)

Wild Street and Dedicated Performance
For an application where performance is desired over streetability comfort. The heads listed below are for larger cubic inch big blocks where the airflow demands are greater or highway driving where the engine does not have to lumber through the gears to get to cruising speed often. Once you get to cruising speed however, these heads should provide all the flow you need or want.
Cylinder heads in the dedicated performance category will do well with intake and exhaust upgrades that maximize the flow characteristics. Large port openings and runner volumes along with larger valves and valve train set up for higher lift are the standards of a wild street or dedicated performance head.
edl-60499_w.jpg

Report this image
Edelbrock High Compression 454-O aluminum cylinder head.

Edelbrock High Compression 454-O (#60499) 50 state legal
Perfect for:
Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 290 cc
Combustion Chamber: Proprietary Semi Open Style 100 cc
  • Additional Specs:
    • Part Number: 60499
    • Intake Port Shape: Oval
    • Exhaust Runner Volume: 110 cc
    • Exhaust Port Shape: Square
    • Intake Valve Diameter: 2.190″
    • Intake Valve Angle: 26°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 26°
    • Maximum Valve Lift: 0.700″
    • Springs Per Valve: Single
    • Retainer Locks: 7°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
tfs-41400001_w.jpg

Report this image
Trick Flow Specialties PowerPort 320 aluminum cylinder heads.

Trick Flow Specialties PowerPort 320
Perfect for:
Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,950 per set
Intake Runner: 320 cc
Combustion Chamber: Open Chamber 122 cc
  • Additional Specs:
    • Part Number: TFS-41400001 or TFS-41400002
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 137 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.700″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
Patriot Performance Freedom Series (#2216)

Patriot-2214.jpg

Report this image
Patriot Performance Freedom Series 2216 aluminum cylinder heads.

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,900 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc
  • Additional Specs:
    • Part Number: 2216
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 125 cc
    • Exhaust Port Shape: Round
    • Intake Valve Diameter: 2.300″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.800″
    • Springs Per Valve: Triple
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1966-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV (1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
RHS Pro Action 320 cc Solid Roller

RHS-11302-02-a.jpg

Report this image
RHS Pro Action 320 cc Solid Roller cast iron cylinder head.

Perfect for: Wild Street Performance or Dedicated Performance
Material: Aluminum
Cost: $1,780 per set
Intake Runner: 320 cc
Combustion Chamber: Proprietary 119 cc
  • Additional Specs:
    • Part Number: 11301-03
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 135 cc
    • Exhaust Port Shape: Rectangular
    • Intake Valve Diameter: 2.250″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.750″
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
RHS-11302-02-a.jpg

Report this image
RHS Pro Action 360 cc Solid Roller cast iron cylinder head.

RHS Pro Action 360 cc
Perfect for:
Wild Street Performance or Dedicated Performance
Material: Cast Iron
Cost: $1,780 per set
Intake Runner: 360 cc
Combustion Chamber: Proprietary 119 cc
  • Additional Specs:
    • Part Number: 11302-02 (Hydraulic Roller)or 11302-03 (Solid Roller)
    • Intake Port Shape: Rectangular
    • Exhaust Runner Volume: 135 cc
    • Exhaust Port Shape: Rectangular
    • Intake Valve Diameter: 2.300″
    • Intake Valve Angle: 24°
    • Exhaust Valve Diameter: 1.880″
    • Exhaust Valve Angle: 15°
    • Maximum Valve Lift: 0.600″ (11302-02) / 0.750″ (11302-03)
    • Springs Per Valve: Dual
    • Retainer Locks: 10°
    • Valve Train: Standard BBC 7/16” Stud Mount
    • Guideplates: Hardened Steel, 3/8″ Pushrod size
    • Application: 396 ci Mark IV (1965-1970), 402 ci Mark IV (1970-1972), 427 ci Mark IV(1966-1969), 454 ci Mark IV (1970-1990), 454 ci Gen V (1991-1995), 454 ci Gen VI (1996-2000)
The Final Word
It’s been said that the terms “budget” and “big block” don’t go together and qualify as an oxymoron when used together. However, the cylinder heads listed in our guide above are well within the range of what can be considered budget friendly. Nan Gelhard of Summit Racing Equipment emphasized that point by saying; “When you talk about dollars per horsepower you can see how it changes as you go from street to strip.”
Whether you have a stock big block that you salvaged from the wrecking yard and are looking for some modern technology heads to bolt on, or if you want to beef up your daily driver to take it to the drag strip occasionally, we’ve got you covered in one of the budget friendly categories listed above.
Billy Mitchell Jr. from World Products encourages enthusiasts to call the tech lines or work with your engine builder. “It’s important to marry the runner size and port shape to the cubic inch size of the engine,” says Mitchell. Chad Bowling of Patriot Performance also recommended working with your engine builder on the engine internals like camshaft before picking a set of assembled heads, “Most aftermarket head manufacturers offer cylinder heads in a variety of spring packages from hydraulic flat tappet to solid roller,” Bowling states. The final word is that it is OK to use this guide as you would any other guide, as a means of gathering information to talk with your engine builder about the best method of achieving your goals.
http://www.superchevy.com/how-to/project-cars/sucp-1208-big-block-heads-shootout-the-o-vs-r/
Sources


Dart Machinery
Phone: 248-362-1188

Edelbrock
Phone: 310-781-2222

Patriot Performance
Phone: 888-462-8276 FREE


RHS
Phone: 877-776-4323 FREE

Summit Racing
Phone: 330-630-0240

Trick Flow Specialties
Phone: 330-630-1555


World Products
Phone: 631-981-1918

http://www.jegs.com/p/Chevrolet-Per...w-Tie-Aluminum-Cylinder-Heads/761642/10002/-1

http://www.superchevy.com/how-to/project-cars/sucp-1208-big-block-heads-shootout-the-o-vs-r/

Big-Block Heads Shootout - The Big O Vs. The Big R
Oval ports and rectangular port heads
Richard Holdener Jul 18, 2012 1 Comment(s)
View Full Gallery
Two issues back, we subjected a 468-inch big-block Chevy to a variety of different oval-port cylinder heads, ranging from stock peanut-port-style heads to full CNC-ported versions (see “The Big O”). In that story, we attempted to dispel the myth that any powerful big-block combination must include rectangular-port cylinder heads. Equipped with the right oval-port heads, the 468 easily exceeded 600 hp on the engine dyno. Most of the oval-port heads tested in part 1 offered airflow that would support another 100 hp on the right combination.

Contrary to popular opinion, our combination was limiting the potential of the oval-port cylinder heads, not the other way around. It is true that all of the factory performance big-blocks sported rectangular-port heads back in the day, but much has changed since the first muscle car era. Not only does a good set of aftermarket oval-port heads outflow the factory rec-port stuff, it does so with reduced port volume. Big, lazy ports are ideally suited for neither performance nor street use, while smaller, efficient ports offer the best of both worlds. Nowhere was this more evident than in the fact that a couple of manufacturers chose to supply oval-port heads once again on this larger (and more powerful) 496 test engine.

Top Searches
  • News
  • Cars
  • Neon
  • Global West 65 Chevelle Autocross Run




A common stroker displacement, our 496 was the result of combining a 0.060-inch overbore with a 4.25-inch stroker crank. Our BBC rotating assembly came from the experts at Scat Enterprises. The BBC combination featured a 4340 forged steel crank combined with a set of matching 6.385-inch, I-beam rods. We chose a Scat crankshaft design specifically for our late-model, one-piece, four-bolt, Gen-6 block. The Scat crank and rods were combined with a set of forged pistons from JE. Offered as part of their SRP line up, the JE Pistons featured 18cc domes to produce a static compression ratio of 10.0:1 with typical 120cc combustion chambers.


The short-block was built not to maximize power production, but rather to demonstrate what is possible for street use in a performance driver. We wanted all of our testing to be run on pump gas, so we kept the static compression at a reasonable level. L&R Automotive was responsible for machining and balancing of the combination, while Total Seal came through with a set of performance rings to ensure proper sealing.

The displacement ensured that our 496 would be more powerful than the 468 used in part 1, but we hedged our bets with the installation of a wilder cam profile as well. Balancing the street/performance theme, we chose a small solid roller profile from Comp Cams. The 300BR-14 offered 0.652 lift, a 255/262 duration split and 114-degree LSA. To work in the Gen-6 block, the cam was teamed with a set of 0.300-tall solid roller lifters and a double roller timing chain.

Since the cam and timing chain were designed for a Gen-4 block, it was necessary to eliminate the factory cam retaining plate in favor of a traditional cam button. The swap also required the use of a custom front cover (PN217) from Comp Cams to provide the necessary room for the double-roller chain (factory Gen-6 covers must be run with a single-roller chain).

Finishing touches on the test mill included an Edelbrock Victor Jr. 454-R intake, a Holley 950 HP carb and SFI-approved, neutral damper from Procomp Electronics.

Prior to running the test engine, all of the heads were treated to flow bench testing to correlate the flow potential to the power gains. In truth, heads like the Brodix BB-3 Xtra O offered over 400 cfm--enough to support more than 800 hp. We were just scratching the surface or their potential with our 496 street/strip combination. After bench testing, we subjected the heads to port and chamber volume measurements. Since the compression ration is a function of the chamber volume, chamber size has a significant effect on the power curve (to the tune of 3-4 percent per point). Measurements indicated that our test heads varied greatly, from a low of 107cc to a high of 123cc. Bear this in mind when viewing the power numbers.

It is again worth mentioning that though this was originally to be a rec-port-only head test (to follow the oval-ports tested in part 1), some of the manufacturers supplied oval-port heads for this 496. Don't look down you noses at oval-port heads, as testing from both stories suggests that if anything, oval is the new square.



Test 1: Stock GM 088 Iron

Prior to running any of the aftermarket heads we had to establish a baseline by running the stockers. We chose a set of 088 castings that featured 316cc intake ports, 121cc exhaust ports and 123cc combustion chambers. The airflow data suggested that the stock iron heads would support over 650 hp, but on this 496, the heads managed to produce peak numbers of 630 hp at 6,600 rpm and 577 lb-ft of torque at 5,300 rpm. While 630 hp would make a serious street motor, we would see that the right head choice on this application would add nearly 100 hp to that total.




  • GM rectangular port castings
  • Retail Price-NA
  • Intake Valve Size-2.19
  • Exhaust Valve Size-1.88
  • Intake Port Vol-316 cc
  • Exhaust Port-121 cc
  • Chamber Volume-123 cc
  • Peak Power- 630 @ 6,600 rpm
  • Peak Torque- 577 lb-ft @ 5,300 rpm
  • Avg HP (3,500-6,500)-532.4
  • Avg TQ (3,500-6,500)- 560.5 lb-
  • TQ @ 4,000 RPM - 562.7lb-ft
Flow Data: CFM @ 28-ins
Stock 088
Lift In Ex
0.050 32 27
0.100 77 56
0.200 144 112
0.300 206 142
0.400 245 166
0.500 289 188
0.600 320 192
0.700 334 197
0.800 335 201




Test 2: Summit Racing Iron

Many would dismiss the iron heads simply for the weight savings, but don't count them out, especially when you consider the price and performance. These rectangular port iron heads from Summit Racing offered surprising bang for the buck. The Summit Racing head upgrade improved the power output of the 496 from 630 hp and 577 lb-ft to 688 hp and 607 lb-ft. This was all the more impressive considering the fact that the heads cost just $750 bucks each, assembled. Toss in the fact that the Summit heads flow only marginally better than the stock heads and share the same combustion chamber volume. If you are looking for iron heads on a budget, look no further than Summit Racing.




  • Retail Price-$749
  • Intake Valve Size-2.25
  • Exhaust Valve Size-1.88
  • Intake Port Vol-309 cc
  • Exhaust Port Vol-127 cc
  • Chamber Volume-122 cc
  • Peak Power- 688 hp @ 6,600 rpm
  • Peak Torque- 607 lb-ft @ 5,400 rpm
  • Ave HP (3,500-6,500)-555.5
  • Ave TQ (3,500-6,500)-582.1
  • TQ @ 4,000 RPM-563.3 lb-ft

Summit Racing Iron
Flow Data: CFM @ 28-ins
Lift In Ex
.050 34 34
.100 69 69
.200 146 109
.300 204 155
.400 264 192
.500 309 223
.600 340 246
.700 323 262
.800 330 273




Test 3: Procomp Electronics Rec-Port CNC

The aluminum heads from Procomp Electronics combined the largest port volume and (nearly) peak flow numbers with the lowest retail cost. The intake port volume measured a sizable 369cc, while the exhaust checked in at 157cc. This head configuration would be much more at home on a larger displacement, higher horsepower application, but how can you argue with aluminum BBC heads that flowed over 400 cfm for around $600? Equipped with the Procomp heads, the BBC stroker pumped out 690 hp and 600 lb-ft of torque. We suspect the large port volume and sizable combustion chamber hurt torque and power on this application, as many of the other heads featured smaller chambers and port volumes. We'd like to see this head strut its stuff on a high-compression 572, but for our 496, it was likely just too big.




  • Retail Price-$625
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-369 cc
  • Exhaust Port Vol-157 cc
  • Chamber Volume-123 cc
  • Peak Power- 690 hp @ 6,300 rpm
  • Peak Torque- 600 lb-ft @ 5,500 rpm
  • Ave HP (3,500-6,500)-554.2 hp
  • Ave TQ (3,500-6,500)- 581 lb-ft
  • Tq @ 4,000 RPM-568.3 lb-ft

Procomp Electronics BBC Rec-Port CNC
Flow Data: CFM @ 28-ins
Lift In Ex
.050 35 31
.100 70 67
.200 152 132
.300 234 175
.400 294 206
.500 336 231
.600 364 251
.700 389 267
.800 403 279




Test 4: Trick Flow Specialties PowerPort 360 Heads

Like the Procomp heads, the PowerPort 360s from Trick Flow Specialties were probably a tad on the big side for the 496. With intake ports that measured 357cc, the impressive PowerPorts would be more at home on a big-block exceeding 500 cubic inches. With peak intake flow numbers of 384 cfm, the heads we capable of supporting over 750 hp, but on our 496 manage 691 hp and 603 lb-ft of torque. The PowerPort heads shared the large (122cc) combustion chamber volume of the stock heads and came in at a cost-effective $1,229 (through Summit Racing).




  • Retail Price-$1229
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-357 cc
  • Exhaust Port Vol-134 cc
  • Chamber Volume-122 cc
  • Peak Power- 691 hp @ 6,400 rpm
  • Peak Torque- 603 lb-ft @ 5,400 rpm
  • Ave HP (3,500-6,500)-555.3
  • Ave TQ (3,500-6,500)- 581.9 lb-ft
  • TQ @ 4,000 RPM-562.3 lb-ft

Trick Flow Specialties PowerPort 360 head
Flow Data: CFM @ 28-ins
Lift In Ex
.050 35 30
.100 72 61
.200 148 125
.300 217 168
.400 275 198
.500 325 227
.600 360 246
.700 376 261
.800 384 273




Test 5: Brodix BB-3 Xtra 332

The new Brodix BB-3 Xtra 332 heads were not quite a rec-port head nor were they a conventional oval (or peanut) port head. They were somewhere in the middle, more like a rectangular-port with rounded corners. In truth, use of the 454-R (rec-port) intake may have hindered the power potential of the Brodix heads more than others due to the port mismatch. One thing for certain is that the Brodix heads topped all comers in terms of airflow with peak numbers of 409 cfm. Capable of supporting over 800 hp, our 496 produced 705 hp and 624 lb-ft of torque. We would love to port-match an intake to these heads in an attempt to translate all that airflow potential into power.




  • Retail Price-$1840
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-335 cc
  • Exhaust Port Vol-133 cc
  • Chamber Volume-115 cc
  • Peak Power- 705 hp @ 6,400 rpm
  • Peak Torque- 624 lb-ft @ 5,200 rpm
  • Ave HP (3,500-6,500)-574.6
  • Ave TQ (3,500-6,500)- 602.7 lb-ft
  • TQ @ 4,000 RPM-585.7 lb-ft
Brodix BB-3 Xtra 33
Flow Data: CFM @ 28-ins
Lift In Ex
.050 33 31
.100 66 69
.200 147 120
.300 211 173
.400 273 221
.500 333 256
.600 380 277
.700 409 286
.800 403 296




Test 6: Dart Pro 1 335

The Pro 1 name from Dart has always meant power and this test illustrates that the name still carries some weight. For our street/strip 496 BBC, Dart supplied a set of its CNC-ported 335 heads. With flow numbers that reached nearly 400 cfm, the Dart Pro 1s were another set of 800-hp heads in search of a motor. The Dart Pro 1 heads featured rolled valve angles and raised exhaust ports to improve flow and power, but remained compatible with stock accessories. Run on the dyno, the big-block produced 717 hp and 619 lb-ft of torque. Equipped with a smaller chamber shared by the AFR and Edelbrock heads, the Dart would likely be right in the hunt for maximum power.




  • Retail Price-$2021
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-303 cc
  • Exhaust Port Vol-137 cc
  • Chamber Volume-122 cc
  • Peak Power- 717 hp @ 6,500 rpm
  • Peak Torque- 619 lb-ft @ 5,600 rpm
  • Ave HP (3,500-6,500)-568.0
  • Ave TQ (3,500-6,500)-594.3 lb-ft
  • TQ @ 4,000 RPM-572.5 lb-ft

Dart Pro 1 335
Flow Data: CFM @ 28-ins
Lift In Ex
.050 34 29
.100 69 61
.200 148 125
.300 228 181
.400 294 219
.500 336 249
.600 376 271
.700 398 281
.800 399 289




Test 7: Edelbrock E-CNC 355

Edelbrock has stepped up in a big way recently with new performance offerings and these E-CNC 335 heads are a perfect example. Proudly made in the USA, the E-CNC heads offered plenty of flow, peaking at 391 cfm on the intake and 285 cfm on the exhaust. Sporting the smallest combustion chamber of the bunch at 107cc, the Edelbrock heads produced the highest static compression ratio. Naturally this helped power, allowing the E-CNC heads to produce 723 hp and 627 lb-ft of torque.




  • Retail Price-$1,630 (required spring upgrade)
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-353cc
  • Chamber Volume-107 cc
  • Exhaust Port Vol-135 cc
  • Peak Power- 723 hp @ 6,500 rpm
  • Peak Torque- 627 lb-ft @ 5,600 rpm
  • Ave HP (3,500-6,500)-573.5 hp
  • Ave TQ (3,500-6,500)- 599.9 lb-ft
  • TQ @ 4,000 RPM-574.0 lb-ft

Edelbrock E-CNC 355
Flow Data: CFM @ 28-ins
Lift In Ex
.050 33 29
.100 73 61
.200 148 132
.300 224 185
.400 283 226
.500 334 252
.600 364 270
.700 385 278
.800 381 285




Test 8 AFR Magnum 300 Oval

It takes more than just big flow numbers to make power, and these Airflow Research heads proved that. In fact, when asked to supply rec-port heads for this test, they opted to instead send over a set of oval-port heads. It new 300cc Magnum heads did not offer the highest peak flow numbers, topping out at 383 cfm (at .650 lift), but when combined with exceptional mid-lift flow and an efficient chamber design, the results were enough impressive. Power production is all about the combination of components working together and on this 496, the AFR Magnum 300 heads proved to be the optimum combination by producing 729 hp and 639 lb-ft of torque.




  • Retail Price-$1,559
  • Intake Valve Size-2.30
  • Exhaust Valve Size-1.88
  • Intake Port Vol-300 cc
  • Exhaust Port Vol-123 cc
  • Chamber Volume-110 cc
  • Peak Power- 729 hp @ 6,500 rpm
  • Peak Torque- 639 lb-ft @ 5,400 rpm
  • Avg HP (3,500-6,500)-584.1
  • Avg TQ (3,500-6,500)-611.4 lb-ft
  • TQ @ 4,000 rpm-587.0 lb-ft

AFR Magnum 300 Oval
Flow Data: CFM @ 28-ins
Lift In Ex
.050 34 32
.100 74 62
.200 153 126
.300 233 198
.400 296 237
.500 345 263
.600 377 277
.700 371 288
.800 365 296


sucp_1208_14_oval_rectangular_port_heads_the_big_vs_r_.jpg
38/38
21 The combustion chamber of each cylinder head tested was measured.
 
Last edited:

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
P
Michael Ray
Polishing a Set of Sneakers
http://garage.grumpysperformance.co...ng-combustion-chambers.2630/page-3#post-77963
blueprint engine blocks
https://www.jegs.com/v/Blueprint-En...brand&storeId=10001&catalogId=10002&langId=-1

DART BLOCKS
http://dartheads.com/product-category/big-block-chevy/blocks/

world products blocks
https://www.billmitchellproducts.com/engine-blocks/

G.M. performance
https://www.gmperformancemotor.com/category/LS196.html

http://www.maliburacing.com/patrick_budd_article.htm
5827.jpg

5828.jpg

Not long ago there was an article in one of the car mags about what it takes to build and maintain a ten-second street and strip car. The article made it sound like getting a ‘real’ street car into the tens was akin to splitting atoms, and a bank heist would be required to fund the operation. Well, I can promise you it isn’t so, and I’ll detail two similar, yet different examples to back it up. The average home assembler can build either engine for far less than $5000 from carburetor to oilpan. Heck, one of these tanks goes 9’s, so it can’t be all that hard.

Money and car crafting have long gone hand in hand, and the crafter with the most of it tends to win the most trophies. Brains, however, especially the kind I call ‘woodchuck engineering’ can be the great equalizer. Tuning, the patient one change at a time variety, can transform a lazy also ran to the kind of car that leaves you scratching your head asking, “what does this guy know”? So too can some extra thought placed into the combination and compatibility of the parts selected. I’ve often said that if racers spent half as much time researching the right part, instead of researching the cheapest price, they’d be much further ahead, both in terms of performance and budget. Before we go and get our ‘Woodchuck Phd.’ however, lets cover some of the real basics of street hero construction.
before you spend a good deal of money porting and un-shrouding any iron cylinder heads, keep in mind aluminum heads are easily repaired in a skilled and experienced automotive machine shop thats equipped to do those repairs but damaged iron cylinder heads are either much harder to repair or good door stops
http://garage.grumpysperformance.com/index.php?threads/iron-vs-aluminum-heads.389/#post-7266

First of all, throw most of your pre conceptions of what makes a car streetable right out the window when you decide to go fast. All those weak-kneed vacuum secondary, dual planed induction systems need to be on your tow unit, not your Saturday night bruiser. All those handy-dandy cam charts that suggest paltry little lift and duration figures? They’re perfect for the birdcage. Torque does have it’s place, and it’s very important when we’re dealing with a heavy street legal car, but it needs to be higher in the rpm range than these suggested grinds will offer. We need torque at the shift recovery point, to accelerate the car off the bottom of the gear change. We can still have a reasonable idle, predictable brake feel, and good low end throttle response. We may not be able to fire up the air conditioner and lift the headlight doors while we pump the brakes, but we really want to go drag racing, not autocrossing, right? I also suggest a rather high compression ratio; and this is where I part company with many of the ‘purists’, that insist a street car must run pump gas. Well, since this build-up requires using heads that don’t have hardened seats, (they require leaded fuel to avoid seat recession) and it’s the compression that allows the use of more aggressive cam timing, (without murdering low speed torque) it’s the cheapest power adder we can use. Look at it this way- the average race gas costs 1.50 more per gallon than premium, and even if you burn up three 55 gallon drums a summer, that’s a $247.50 upcharge a year. We don’t even want to talk about how much it costs with trick parts to recover the lost power from high compression. We don’t need a roller, but solid lifter flat-tappet cams are a big help, and we’ll need a somewhat loose converter. Many of the better trans shops can now build you a piece that will ‘flash’ high while maintaining decent part throttle manners.

Both of the engines we are going to discuss here are garden variety, low buck, oval port Big Block Chevrolets, one a 468 inch open chamber engine and the other a 432 inch closed chamber mill we’ll use a bit of nitrous with. We’ll be discussing them together because most of the concepts and operations apply to both engines; I’ll specify where and why the buildups differ. The ideas we discuss here will cross over to most marques, so you Ford and Mopar guys don’t need to flip the page just yet.

My good friend Mike Nerwin has been a hardcore footbrake racer for as long as I can remember. He’d also been ‘the chased’ for equally as long, meaning he left first at the Saturday night brackets because he was fairly slow. Mike came to me last fall with a desire to go quicker, and faster, so he could keep the competition in his view a higher percentage of the time. He also wanted a package that had the necessary street manners to allow him to cruise it whenever he chose. Lee Martin is a die-hard street enthusiast that only goes to the track to see how quick he can go. He already owned a wounded 427, and his budget demanded we make good use of it. His 10” street tire Regal needs to be dead reliable while quick enough to part in the ‘front row’ of the local cruise night.

My first question, as it is with all customers, was how fast do they want to go? That question needs to be answered honestly, because you can’t build a 6000 square foot mansion on sand, as you can’t make 800 horsepower with 3/8 rods. My next question was how much money do you have? This has more to do with feeding the beast once it’s completed than it does the cost of the build-up. A finished car that’s too expensive to race or enjoy doesn’t do anyone any good. Third and last, I ask how skilled an assembler the customer is, because I may be able to give them an assembled shortblock and have them save money by completing the rest of the work themselves. Mike wanted to go high tens, and had a fairly short budget, although he understood the flexibility some compression allowed me so he’d buck up for ‘cheap’ race gas. He also has a tank for a car, 3600 lbs of second generation f-body. Since it’s virtually impossible to get him to lighten anything up, I knew I’d need around 600 horsepower and 550 ft/lbs. of torque to reach his target. Lee’s goals were a bit more modest without N20, but once he turned the bottle on, the wanted a solid nine second timeslip. He also has what amounts to a battleship, a 3500 lb. Regal. This meant we needed at least 550 horses before we engaged the spray. I again explained the added flexibility of race gas and how higher compression would make the package less peaky and easier to drive, and he agreed the added cost of fuel wasn’t a deterrent. I figured we could get him in the nines, and run a few high tens on horsepower, as well.

Within a week, I had a couple of cores cluttering up my garage. One was a cast crank, oval port 454 and the other a wounded, albeit complete, 427. The 454 was a two-bolt block, 781 headed smog era deluxe. Lee’s 427 core came with closed chamber heads, and a steel crank. He also had the right lowbuck intake, an un-ported Holley Strip Dominator. While it’s nice to be able to work with the latest aftermarket heads and the like, this project is about making do with what we have. We were definitely polishing a couple of sneakers, but that was part of the challenge. After dis-assembling everything, we found the 454 had a nice, straight, virgin crank and a .030 over block. The 427 wasn’t quite so lucky. It had a couple of cracked pistons, broken rings, and significant bore wear. It would require at least a .030 overbore to clean up the mess. After inspecting the head castings, I didn’t see any major flaws or cracks. They both had the typical seat recession, but they were receiving 2.19/188 valves, so it didn’t necessitate new seats. Since I consider myself just slightly better than a horrible head porter, and consider them both very good friends, I figured this would make a good exercise in what we could get done by investing the one thing a low budget guy can afford: time.

The key to any good engine is its induction package. Good heads flow large volumes of air yet have a conservative enough cross sectional area to assure good ‘recovery’ or velocity as the engine speed transitions on gear changes. If we were racing a 1600 lb. dragster, these castings would have hit the dumpster. The reality was these cars weigh 3500 lbs or more and both carry a streetable 4.10 gear. When matched with 30+ inch tires, these combinations are a bit steep for a big intake runner. I knew there’s not a good short side in the factory heads (the area under the valve where it transitions the port floor) and the finished port volume would limit high rpm breathing. I therefore concentrated on straightening and blending the port to the valve job, working a consistent taper down the runner. We were trying to emphasize low lift flow and velocity, because the cams that would live on the street have less than .600 net lift, once you subtract lash and deflection. Keep in mind, we’re not trying to emulate Sonny Leonard here, so we’re leaving the general shape of the port as GM created it.

I took both set of heads to Ronnie Jewell’s place, a fellow graduate of the Woodchuck University, and had him rough in the new valve jobs of the previously small valve castings. No trick Serdi’s here, just a hand held grinder and some patience. This gave me an interior angle to port to. The open chamber heads on the 468 received the more radical port work, as I felt the swept volume of the engine would require more volume to fill the cylinder. Keep in mind as you look at the photos, we didn’t have the aid of a flowbench as I modified the ports. I had to rely on common sense and educated guesses as I removed material, and admittedly, some good cuts may have been offset by bad ones. The 468’s combustion chambers also received more aggressive work, as I laid the quench side back to aid in the blowdown of the cylinder. Exhaust gasses are purported to actually flow backwards on the GM heads due to the nearly non-existent short side radius. The cut into the quench area aids the gases negotiation of the tight turn. This mod may have been even more beneficial on the nitrous aided 427, but truth be told, I did those heads first and didn’t get as involved with the combustion chamber mods until I did the 468 heads. Lee got the short end of the stick, in that respect. I raised the roofs of both heads’ exhaust ports to the gasket, and blended back into the bowl. I removed significant material on the longside radius, directly under the venturi in an attempt to enhance the low-pressure area beneath the valve seat. This low-pressure area helps draw the spent charge out of the engine and the material removal gives the turning gases more room to make the turn. The accompanying charts show how effective this move was. I directed more of my efforts on the 427’s heads to providing a bit more room on the spark plug side of the chamber to facilitate intake flow. The intake runners of both heads received essentially the same cuts, which are detailed in the accompanying photos. (It is important to note that the heads were flowed only after they were complete, and no modifications to them were performed after we had the flowbench data.)

While I was fiddling with the heads, the blocks were at Carl McQuillen’s machine shop in LeRoy, New York. Carl was a real hitter back in the beginning of the street legal movement, and has parlayed his notoriety into a thriving ‘compound’ in Western NY. He fleshes out many of GM’s brainstorms with his 5 axis CNC machines, EDM’s and skilled help. His shop is spotless, and the work dead-on. We ordered Mike some new pistons, and brought the ones we scored out of the classifieds for Lee’s piece. Once Mike’s pistons arrived, both blocks were over bored to their respective diameters (the 468 to 4.31 and the 427 to 4.28, bringing the cubic inch to 432) and the decks squared and to zeroed. Since Mike’s 468 was a bit higher buck, we had the edges of the bores oblonged to the edges of the gasket’s bore. We then hand blended the cuts to .100 away from the top ring. The chambers of GM heads hang over the bore edges, so while I’m not positive this trick aids airflow, it makes sense on paper. Both blocks were bored and honed with torque plates to ensure good ring seal. Low buck doesn’t mean low effort- meaning attention to the details can make even a modest effort piece run better than expected. Why port the heads and not do what it takes to seal the cylinders? I found them each a set of 7/16 GM rods to replace their ‘peanut butter’ 3/8 rods and had the assemblies balanced to a new ATI damper.

While the lower end components were away, I had Ultradyne grind up a custom cam for Mike’s 468 and Comp Cams whip one up for Lee’s 432. I am a strong believer of big, soft exhaust lobes and crisp aggressive intake lobes. This accomplishes two things, it allows the exhaust plenty of time to get out of the cylinder, and the quicker action of the intake lobe can hold the intake valve closed a smidgen longer reducing dilution while having enough valve opening at peak piston velocity, critical to good cylinder filling. The more controlled exhaust valve action is extra insurance against piston-smacking clearance problems as well. Both cams are similar, with duration in the mid 260’s on the intake and upper 270’s on the exhaust. Gross lift is in the .650 range on the intake and the .630 range on the exhaust. The main difference is in the lobe separation angle; the naturally aspirated 468’s cam was ground on a 108 lsa while the nitrous aided 432 received 110 degrees of separation. A lot of really wordy articles have described the reason for running different separation angles, so let me try to describe the way I understand it very briefly. A tight, or numerically smaller angle delays the exhaust valve opening and closing, trapping more cylinder pressure and increasing overlap, or the time both valves are open. This makes use of the engine’s escaping exhaust gases to pull in fresh charge. The negative is that rpm increases, it takes work for the piston to push the exhaust out and some of the charge starts to fly out the exhaust port during overlap. The 110 lsa on the N20 cam opens the exhaust valve earlier, blowing the cylinder down quicker, and saves the piston from having to push all the extra junk created when the nitrous is on. We don’t want the overlap, because there is so much more pressure with nitrous that there is a tendency for the charge to fly back up the intake tract if the valve is opened too soon. (This is hardly a ‘max effort’ nitrous grind, as Lee won’t be using more than 200 horse of the stuff out of respect for the swap meet forgings.) The 468’s cam was installed at 105 degree intake centerline and the N20 cam went in at 108.

Once the bottom ends for these two engines arrived back home, we gave each of the parts a final close visual inspection. Lee’s 3.76” 427 crank had some scores in it from a sloppy prior assembly, as whoever owned it previously didn’t protect the journal from the rod bolts during assembly. They weren’t deep enough to require a turn, but I polished them with 400-grit sandpaper and a leather strip to be sure. We then mocked everything up to see if either of the engine’s clearances needed adjusting. All the bearing clearances were fine, and there were no exotic tricks as we assembled the shortblocks. Top endgaps for the rings were .018 for the 468 and .022 for the 427 (now 432). The wider gap on the 432 is to reduce the chance of the rings butting with the nitrous on. Nitrous increases cylinder pressure, which creates heat, and encourages the ring to expand. The second rings were .016 for both engines. Piston to valve clearances dictated how much we could cut the heads in search of compression, and we wound up lopping off .030 from the 468 and .060 from the 432. Final compression ratios wound up being 11.83:1 for the 468 and right at 13:1 for the 432. The Strip Dominator Lee had needed a cut to fit the chopped block and heads, but the Edelbrock 454R was just fine as we laid it in place on the 468. Out of respect for the plate nitrous system being installed on Lee’s motor, I radiused the port entries and dividers in the plenum of the Holley. With all the fuel flying around the plenum, nice radiused dividers and walls are cheap insurance against fuel shearing and fallout. The Edelbrock probably would have profited by such a move, but we elected to leave that 5 or so horse on the table and get these things in the cars.

Carburetion for both engines followed suit with the rest of the buildup, as Mike spent a few more bucks and popped for a fresh Pro Systems dominator. Patrick James has a knack for prepping pieces that fit a wide range of applications. The expensive carb may seem out of place with a build such as this, but we saved money in other areas to afford the carb. I’ve personally installed a half dozen or so of his pieces on my customer’s engines, and every one has picked up the program. Lee’s budget dictated we use a box stock carb, so we went with a 950 HP from Holley to top the 432. After break in, we took them both to the dragstrip to see how we fared. The 3600 lb. Camaro went a spinning 10.51 at 129 miles an hour on its second visit to the track! Mike was shifting the 468 at only 6500rpm, a testament to the oval ports’ ability to generate power without high engine speed. Some quick math shows the engine was producing 650 horsepower, in average summer air! Chassis tweaks and launch techniques should put this car in the mid 10.30’s judging from it’s mile per hour. Bear in mind, this car had a tight (by race standards) converter, stalling at 4800 rpm. Part throttle streetability is excellent. Lee’s Regal, sporting a 10” TCI swap meet converter behind the 432 and 10” wide dot tires, reared up and went a 10.95 at 124 on steam, and when we put a 73 pill in the Big Shot plate (about 150 horsepower), it whipped out a 9.98 at 135! We hadn’t even changed a jet or started digging for the hundredths. This thing was making all of 700 horsepower with the nitrous engaged, and since it 60 footed 1.38, there’s plenty of torque to get the car rolling. We’re sure that when the targeted 200 horsepower pills get inserted and we get to the nitty gritty tuning the little 432 will find its way into the 9.50’s.

While these numbers aren’t astounding, they are more than acceptable for the limited cash outlay and scope of the buildups. Small money and respectable et’s aren’t mutually exclusive, and the beauty of these two engines in particular is their ability to create power with very little rpm, reducing the cost of maintenance down the road. Neither of these will ever see the other side of 7000 rpm. Often your competition is overpriced and under thought, leaving you room to exercise your greatest speed part: Your brain. Viva the Woodchuck!

Post Script: Mike Nerwin, always the “tinkerer” decided to try a set of Merlin rectangular ports he scored for a reasonable price from another friend of ours. I performed a very mild bowl blend on them in the past, and knew them to be sound castings. We cc’d the chambers, and they turned out to be 8 cc smaller, resulting in a 1.25 point increase in compression. (11.83 vs. 13.08) A plenum blended Weiand Team G was placed on top, and the rest of the combination was left as is. Weeks of consequent testing were disappointing; the rec ports were consistently .2 slower with an average loss of 2 mph. Mike even removed 75 lbs. from the car in search of the et, but the car still refused to run as it had with the GM oval ports- lighter weight, increased compression and all. Perhaps the intake was the problem, maybe the cam didn’t like the Merlin heads. I really don’t know. I just thought this an interesting twist to throw into the mix… Remember, when bracket racing or cruising the streets, it’s the mid range torque that does the work, and I think this example backs that up
.

Oval Port vs. Rectangular PortBBC Head Comparison




This is a subject that is debated almost as much as BBC vs. SBC. Well thanks to Dave Vandenburg, we can do a side by side comparison to see how they actually compare. This isn't a magazine article that is skewed by advertisers, just the cold-hard facts.
Thanks Dave!



The "Contenders"

1971' LS6 454 Rectangle port heads
Casting #3994026
Intake = 2.30 Exhaust = 1.88
Test date : 02/06/00
Test pressure : 28"
1974' 454 Oval port heads
Casting #366781
Intake = 2.25 Exhaust = 1.88
Test date : 01/03/02
Test pressure : 28"



Dave performed the flow tests of both heads on the exact same SuperFlow flow bench. He also performed the port work on the heads. So variables are kept to a minimum. I don't think you'll find a more appropriate "apples-to-apples" comparison. Here is his description of the work done on the heads:

The rect ports were, in my opinion, "mildly ported". The intake runners were gasket matched, the valve pockets were smoothed out to the runners, and both short sides were cleaned and smoothed... and of course any casting lines were smoothed. There was probably room for some improvements on them but not without removing a bunch of material. I was already concerned with them being 320cc on the intakes that the motor was going to be lazy so I didn't want to make them any bigger. Besides, the only gain was going to be at .600" lift and above. The low lift flow #'s were low and I knew it would only get worse with volume.

The oval port intakes were gasket matched to a Fel-pro intake gasket and was blended back about 2" into the stock cast port. Under the intake valve was blended in the same fashion (out to the stock port) to the full size of the valve right up to the seat. The short side was touched to nock off the high spots. Just the basic bowl blend / gasket match to me. The exhaust was bowl blended to the seat size and down into the stock port as well. I spent some extra time on the short side here. The short side was smoothed and radiused very nicely right up to the seat... and I'm talking less than 1/32nd from the seat and polished as well. I took some material off the top of the exhaust guide and blended out to the roof of the port also but the guide still had an obvious flat spot to it. Both intake and exhaust valves were relieved in the combustion chamber area the same amounts.




The Results!
portbbccv.png


Lift Intake Flow (CFM)
Rect Oval Oval Gain/Loss
.100"
66 73.1 +7.1
.200"
127 140.2 +13.2
.300"
184 211 +27
.400"
234 273.2 +39.2
.500"
284 302.8 +18.8
.600"
319 315.3 -3.7
.650
331 313.8 -17.2
.700"
301.1 -

Lift Exhaust Flow (CFM)
Rect. Oval Oval Gain/Loss
.100"
55 60.8 +5.8
.200"
105 107.7 +2.7
.300"
134 139 +5
.400"
161 165.2 +4.2
.500"
183 186.4 +3.4
.600"
199 202.3 +3.3
.650"
205 208.4 +3.4
.700"
216.5
-
As you can see, the numbers speak for themselves. The oval port heads kick butt up until .650" lift, then the rectangular ports take off. The majority of all street/strip or weekend warrior applications are not running over .650" lift cams. Also, you have to take into consideration that the valve is at max lift at only approximately 8% of the time. So, low and mid lift flow numbers are VERY important. That's where the oval port heads really stand out. Technically, there is no winner or loser. It all depends on the application. This is excellent information to prove that oval port heads are the best choice for "milder" applications that are under 500 CI and have a max RPM in the 6500 range. No doubt, the rectangular port heads have their place. They are the choice for ALL-OUT performance. But for less radical combinations, the oval ports are the choice.


http://www.superchevy.com/how-to/project-cars/sucp-1208-big-block-heads-shootout-the-o-vs-r/

More Facts

Here is flow bench results from Patrick Budd at Budd Performance. He is the Competition Director for the NSCA and a racer. Patrick emailed this info to me long ago, but I lost it. Luckily Dave had a copy and sent them to me.

bbcgasketma.png


ovalpts.jpg

ovalpts2.jpg
 
Last edited:
8

87vette81big

Guest
Interesting article Grumpy.
Finish reading on.my laptop .
Older article because Race gas costed $4.25 per gallon.
Its about $10 per gallon now.
But the Benifits are huge.
 
Top