build a 496 stroker BBC


Staff member
the 496 BBC is basically the BBC 454 version of the 350 SBC, being stroked to 383,
in a SBC, you bore the block .030 and stroke the standard 350 from 3.48" to 3.75"
on the BBC you bore the 427 BBC or 454 BBC block .060 and stroke it an additional ...1/4 or 1/2 inch from the stock 427s 3.76" 0r 454s 4.0" stroke, standard bore on the 454 is 4.25 and if you just stroke the standard bore block you get a 489 displacement

the 496 (4.310 bore)(.060 over) and 4.25 stroke (4.25 stroker)vs the stock 4.0" will drop into some blocks but most require minor clearance work.
btw the 6.385" rod combo with the larger counterweights is prefered over the stock 6.135" rod version due to ballance and clearancing issues, counterweights clearing the piston skirts, and having less machine work to ballance in many cases, don,t forget the oil pan usually needs to be checked or modified for clearance, with some rods

results are usually impressive if the compression ratio is in the 10:1 range or higher and the cam is in the 235 durration @.050 lift range or HIGHER matching the engines other components and drive train gearing ... Cams2.html

has some excellent values in flat tappet solid lifter performance cams for the BBC stroker

Chevrolet Performance Camshaft; Part Number SS4254
works very effectively in a 10.6:1 cpr 496 combo with decent heads and an intake

Chevrolet Performance Camshaft; Part Number SS4265

boost the cpr to 11.5:1 and this cam can produce good hp
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Staff member
thought you guys might like to see a 489-496 BBC dyno sheet posted on a differant forum

"Anyway for all asking, here is the short version

489, Brodix Oval, 10.3, Ede Performer RPM, Pro Systems HP 1000 w/ Dominator metering
LRE aluminum rockers, Comp custom 242/.246 - 621/.615 hyd roller 114 LSA, 109 ICL, 91 pump 2" dyno headers"



differant BBC engine , but VERY CLEAN/IMPRESSIVE looking engine


having a good high capacity baffled oil pan on your engine adds considerably to its potential durability and potential life span
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Staff member
4 bolt studded 454 block
10.5:1 compression *Pump gas*
496 4340 rotating, Internal balance, SRP 18cc pistons
AFR 305, CNC chambers millled to 114cc *WOLFPLACE*
Solid roller 267I, 271E, .709I, .690E 109LSA installed at 103ICL *CSTRAUB*
Morel pro series psi lube roller lifters
Jesel shaft rockers
Everwear cam gear, Melonized dist gear
Victor JR, port matched
1" carbspacer
Pro systems HP1000
5" K&N
2" Hooker super comp headers

TH400 4500 edge converter
4.10 gears, 12bolt truetrac posi
28x10.50 tires

66 Chevelle SS
496, Pump gas, no dominator, no spool, no electric fuel pump, no electric water pump, no big tires, full interior...............Just a street car.

1.476 60ft
4.415 330'
6.401 1/8
108.64 mph
8.370 1000ft
10.048 1/4
134.04 mph

66 Chevelle SS
496, Pump gas, no dominator, no spool, no electric fuel pump, no electric water pump, no big tires, full interior...............Just a street car.

almost any 427 or 454 block can be used but the 4 bolt main GEN IV passenger block with the STANDARD 9.8" deck height in good condition will be a reasonable choice, the GEN V and GEN VI are not as MOD FRIENDLY (COST WISE)and theres a few parts interchange issues that while they can be worked around are best avoided, so the first choice is a 1967-1990 427-454 block from most cars or light trucks, motor homes ETC.

a correctly built 496 uses a 1/4 longer than stock 6.385 length rods with 7/16" bolts and larger counter weights to match the longer rods and higher pin height
you can,t use the stock crank or pistons to build a 496 stroker, yes theres kits available that allow the use of the stock 6.135" rods but they are significantly weaker than the aftermarket rods and require more clearancing on the crank/piston skirt area

do yourself a huge favor and buy a matched stroker kit from a single source,
crank,rods,pistons,rings,bearings,damper,flexplate and a matching baffled high volume oil pan and oil pump with pick-up and sellect a combo that matches the heads youll use and allows the correct compression ratio for the cam, durration and rear gearing youll use


Shift kits valve body's, clutches etc. kits vary, and transmission shop technician skills are obviously at varied levels if you elect to have the kit installed professionally, and in most cases , if you have a performance shift kit its not true full manual control, if that's the kit you buy,yes it should kick down, but as always ASK QUESTIONS before you buy any parts or shift kits
generally, full manual control kits will stay in the selected gear regardless of rpm or load, just like a manual transmission, you just don,t have a clutch petal to deal with
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Staff member
yes you CAN build a 496 stroker with the shorter 6.135 stock rod length, but the slightly longer 6.385" connecting rods are much prefered


if you wonder why I suggest using SCAT (H) beam style cap screw connecting rods vs stock or most (I) beam designs this picture should show the increased cam to connecting rod clearance

notice the pin height in the pistons pictured above allow a longer or shorter connecting rod length


heres a selection of commonly available big block chevy connecting rod lengths
now I may be in the small minority here, but I have always given away 3/8" bolt sbc or bbc rods rather than use them and purchased the 7/16" versions or aftermarket 7/16" cap screw rods, WITH the L19 bolt upgrade,the 7/16" rods ARE significantly stronger. rod bolts are critical, high stress items and one of the areas most likely to cause problems at high rpms and loads.
cross sectional area of a 3/8" bolt is approx .11 sq inches, a 7/16" bolt is approx .15 sq inches BTW when you go to buy a ring compressor....this type works far better than the others



BUT! its generally a better idea to use the slightly longer 6.385 rods simply because they leave more clearance for the cranks counter weights, under the piston skirts and allow a lighter /shorter piston, plus (AND THIS CAN BE EXPENSIVE)the shorter rods limiting the diam. of the counter weights can REQUIRE the use of Mallory metal to add weight to the counter weights during the balancing, which gets expensive FAST, in fact the cost of a set of good forged rods will generally be a minor consideration in the total engine build costs, and when you figure the extra cost to balance the assembly and the current rods could be sold, I doubt the true final cost of a new set of connecting rods will be a significant deal block/BBC rods.html block/BBC cranks.html

if your willing to build a RACING ONLY high compression 496, that will require higher octane fuel, you can easilly make very impressive power levels with a decent roller cam and good heads, but look over that beck racing combo, its impressive for the compression and could be used on the street in a lighter car with the correct rear gear and trans combo

heres some info from a different thread that fits here
the very first step would be to buy a few books and read them BEFORE deciding on your course of action

because knowing ALL your options and your goals is mandatory to getting good results
you really should get these books and read them before going any further, it will help a good deal, yeah I KNOW, STARTING BUY BUYING A FEW PARTS IS MORE FUN!, BUT KNOWING EXACTLY WHICH PARTS AND WHY YOU SELLECTED THEM IS SMARTER

heres more bbc info, but don,t let the guys make you think only oval port heads work well! it totally depends on your combo,s rpm range,displacement,gearing,weight,cam timeing,etc
general big block info!
big blocks like more compression, bigger carbs and a slightly larger cam than small blocks if thats what your used to building btw
as they say in hotrodding and breast surgery: "There's no replacement for displacement"

while I see lots of potential in the ls series the displacement and head flows limited copmpared to the BBC ,ID also point out that you can now purchase complete aluminum block aquiped BBC engines up to about 572-605 steel blocks up to 704 cid displacement from several suppliers, and hp levels exceeding 800-1200 hp are comon depending on config in N/A builds, add nitrous or a turbo and 1500 plus hp is easy
remember nearly anything you can do to a 383-427 to make it run better will work even better on a 540-680 bbc s larger displacement, bigger ports and valves, example if TWIN TURBOS on a 383 works wonders, how much better will it work on a correctly built 605 displacement

427 is a good SMALL BLOCK by todays standards

IVE SEEN LOTS OF GUYS DUMP 8K-11K in a SBC engine with TURBOS, superchargers ,trick parts and not equal whats available like this 620 displacement BBC..even the 550 and 454 SBC exceed what many guys spent far more money to build

almost any 427 or 454 block can be used but the 4 bolt main GEN IV passenger block with the STANDARD 9.8" deck height in good condition will be a reasonable choice, the GEN V and GEN VI are not as MOD FRIENDLY (COST WISE)and theres a few parts interchange issues that while they can be worked around are best avoided, so the first choice is a 1967-1990 427-454 block from most cars or light trucks, motor homes ETC.

a correctly built 496 uses a 1/4 longer than stock 6.385 length rods with 7/16" bolts and larger counter weights to match the longer rods and higher pin height
you can,t use the stock crank or pistons to build a 496 stroker, yes theres kits available that allow the use of the stock 6.135" rods but they are significantly weaker than the aftermarket rods and require more clearancing on the crank/piston skirt area

do yourself a huge favor and buy a matched stroker kit from a single source,
crank,rods,pistons,rings,bearings,damper,flex plate and a matching baffled high volume oil pan and oil pump with pick-up and select a combo that matches the heads you'll use and allows the correct compression ratio for the cam, duration and rear gearing you'll use

read these

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Staff member
I had a request a couple years ago to help duplicate a guys old high school hot rod camaro, well the guy had a few parts and a well worn 1968 camaro, and he wanted to basically duplicate his old 427 camaro engine(nostalgia build) but I talked him into a stroker kit to build a 496 big block version, he demanded we use the old original L88 cam, but I talked him into the updated ZL1 version due to the increased displacement,
IVE run both the ZL1 and L88 cams in several 454-496 big blocks with between 11.5:1 and 12.5:1 compression
a lunati LUN402A6 would be a bit more modern version
both run better with higher compression and IVE always found the ZL1 to produce better power, I don,t think either will be ideal in a low compression big block because both need to be spinning in the 4000rpm plus range before they really wake up in my experience, and Ive found a good dual plane intake and a good vacume secondary 850-950cfm carb and open headers works great on both, the last 496 I built with a ZL1 cam had 11:1 cpr (sunoco 260s no longer on all the better gas stations) and an old edelbrock dual plane rectangle close chamber heads heads and a holley 3 barrel, to duplicate a guys high school car it made well over 550 hp and the guy was grinning all the way after we installed it in his 68 camaro 4 speed car with 4.11:1 rear gears
yes he got the old school lope, and metalic sewing machine solid lifter idle sound, and sound and the ability to destroy street tires (even better than his old 427 did)
3925535 ( intake lobe ) L88 cam.Chevys advertised duration is 354,Lash .024

theres certainly advantages to using alcohol ,
significantly cooler engine temps and a bit better power without any doubts.
but one thing I learned using alcohol in any race engine was to be damn sure you remembered,
to run the engine on straight 100% gas,with a dash of MMO,
for a couple minutes before you turn it off and park the car
if you don,t youll have an amazing amount of corrosion related issues in a car thats parked for a week or more between usages

my 1968 corvette with a big block 496, running METHANOL and crower injection, it looked vaguely like this picture,when I tried alcohol for a short time,
mine was Burgundy and a chrome bumper corvette of course
that required a quick disconnect fuel cell, so I could quickly swap fuel tanks,
I had a 15 gallon fuel cell in the corvette, filed with METHANOL, and a quart of MMO, and a jury rigged 5 gallon fuel can, filled with 115 octane gas and a pint of MMO, we carried separately , too the track,
with the proper quick connect connectors to run the car from for a few minutes ,
before we parked it for any length of time to reduce the chances of corrosion.

3959180 Mechanical flat tappet ZL1
I: 327 E: 333
I: 262E: 273
I: .580"E: .620"
I: .024"
E: .026" 110 ZL-1 and LS-7 mechanical lifter competition cam. Good in 427-454. Use spring P/N 3916164.

quote="DO2G"]I’m trying to decide if a 500HP/500Torque SBC crate engine is worth the expense ($8K – $10K).

Currently, I have a L-82 (4 speed) with Brodix IK180 heads, true dual exhaust with Stan’s Tri-Y headers, Lunati 60101 Cam and 3.73 gears.

I have no idea what my HP is today, but would I notice a big difference in buying a 500HP crate motor compared to what I have today?[/quote]

If I still owned a C3 corvette, and had $10K or so to spend on a new engine, theres no question at all in my mind that Id build and install a BIG BLOCK CHEVY,that would have chrome side exhaust and a serious 496-572 big block engine installed in the engine compartment.
500hp SBC are about as common a mustangs and camaros with owners that think they own a fast car, you only live once, build something MEMORABLE and IMPRESSIVE!
I had a 1968 with a full roll cage a 496 BBC and a dana rear at one point and I had lot of memories made in that car, and while it was virtually useless, because any place I drove it I had to park it where I could watch it, and it seemed to attract a police car following it rather rapidly, as I had crower injection sticking out of the hood. it was still a real fun car to drive, as I could smoke street tires effortlessly even from a 60 mph roll.




if you can visualize a chrome bumper corvette similar to this picture with those stack injectors sticking thru the hood in a burgundy colored corvette with larger rear wheel flares a tubed rear with huge tires and a full roll cage you be visualizing something similar
Here is several related threads and dozens of related sub-links that will prove very useful, yes it will require hours to read through them but you'll save weeks of work avoiding mistakes and save hundreds of hours doing the reading and asking any related questions well before you run into potential problems by doing so!
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Staff member
IF your going to build a big block Chevy it usually helps to know your options and longer strokes and rods help.
Id also point out that doing the math before you purchase parts will save you a great deal of wasted cash,
and if that engine your contemplating is intended to exceed about 4200 feet per minute in piston speed or 6200rpm,
you might want too think seriously about 4340 forged steel crank, forged pistons, and rods with 7/16" ARP rod bolts
youll generally want to build a tall deck, engine with longer connecting rods to take full advantage of the tall deck architecture
the deck heights .400 taller so youll generally want connecting rods that are longer on the 4.25", stroke , stroker crank
IVE GENERALLY USED SCAT CRANK ROTATING ASSEMBLIES WITH 7/16" ARP ROD BOLTS and 6.385" 0r 6.535" rods as they are longer to compensate for the .400 taller deck height, a call to SCAT will get you the correct part number for a kit forged and internally balanced rotating assembly kit
Phone: 310 370 5501
10.2 deck minus 1.52 compression height, minus 6.535 rods and 4.25/2= minus 2.125 stroke = .02 so the pistons going to stick above the deck .02 requiring a bit thicker .062 head gasket too get the .040-.042 quench Ill look to



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









Piston compression height is the distance between the centerline of the pin to the flat part of the top of the piston. It's important to know this number when ordering pistons--especially custom ones--so that the piston falls in the right place in relation to the deck surface of the block (where the cylinder head bolts on). To figure out the best compression height, you need to know your block's deck height, the length of your connecting rods, and your crank stroke.

Block deck height is the distance from the centerline of the main journals to the block deck surface. For example, the small-block Chevys we tested last month were delivered at 9.020 inches, though this is commonly machined to 9.00--and giving or taking that 0.020 really makes a difference.

So assume you have a block with a 9.00-inch deck height, 6.000-inch connecting rods, and a stroke of 3.75 inches. First, divide the stroke by two and add that to the rod length: 3.75 / 2 = 1.875, and 1.875 + 6.00 = 7.875. Next, subtract that answer from the deck height: 9.00 – 7.875 = 1.125. So the answer is that the piston compression height should be 1.125 inches.

That will put the top of the piston exactly at the top of the engine block, which is usually best for quench and performance. If you want the piston to be 0.010 above or below the deck, simply add or subtract that amount from the compression height. Easy.

common BB CHEVY piston compression heights are
remember the blocks deck height, minus the piston pin height minus 1/2 the crank stroke will equal the required connecting rod length
the blocks deck height, minus the connecting rod length, minus 1/2 the crank stroke. will equal the required piston pin height
yes its common for a combo to have the piston deck height located .010-.015 above or below the deck of the block so you'll need to select a head gasket thickness that compensates, too allow your engine to get a .038-.044 piston deck to cylinder head QUENCH DISTANCE.

now you can have custom pistons fabricated in almost any configuration in that range and theres obviously a 9.8" standard and a 10.2" tall deck, and aftermarket blocks with deck heights to about 11" tall.

notice the pin height in the pistons pictured above allow a longer or shorter connecting rod length


heres a selection of commonly available big block chevy connecting rod lengths


"That's a lot of cam Grump. In a street car? "
Ive used it in several 10.5:1 compression 496 BBC engines used with manual transmissions and usually 4.11:1 rear gears , in a early nova camaro etc,
heres what DD2000 predicts, I know it regularly shreds 12 bolt stock rear differentials


a lunati LUN402A6 would be a bit more modern version

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)
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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.

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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

21 The combustion chamber of each cylinder head tested was measured.
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Someday Grumpy.

Too far into 2015 now.
455 .