big block head comparison

grumpyvette

Administrator
Staff member
http://www.corvettefever.com/techarticl ... index.html
Cylinder Pressure Note: youll generally want to try hard to maximize the useable compression as the higher the compression before you get into detonation the more efficiently the fuel can be burnt and the more torque the engine can produce, if limited to pump high test 92-93 octane fuel,165 psi # of cylinder pressure is about the best cylinder pressure for Iron heads with 92-93 octane, using pure un-ethanol laced fuel, gasoline. while the faster heat transfer rate of aluminum cylinder heads will usually allow 190psi # as the upper limit or best for aluminum heads.

http://garage.grumpysperformance.co...-about-your-potential-dream-bbc-combos.14607/

http://raceflowdevelopment.com/product/rfd-24-victor-pro-mc/

http://www.wengines.com/BBCweingartner.html

http://www.dragzine.com/tech-stories/engine/ultimate-guide-to-budget-bbc-cylinder-heads-under-2000/

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



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

https://sdparts.com/details/gm-performa ... s/12363392

http://www.summitracing.com/parts/bro-2021012/overview/

http://www.summitracing.com/parts/bro-2061000/overview/

http://www.summitracing.com/parts/afr-2001/overview/

http://www.summitracing.com/parts/edl-60559/overview/

http://www.summitracing.com/parts/edl-60499/overview/

http://www.summitracing.com/parts/drt-1 ... /overview/

http://www.summitracing.com/parts/tfs-4 ... /overview/

http://www.summitracing.com/parts/tfs-4 ... /overview/

http://www.profilerperformance.com/raci ... rted-heads

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

http://www.skipwhiteperformance.com/det ... =BBC-OVP-A
I KNOW ITS A P.I.T.A. but you tend to get what you pay for and Chinese import head casting and machine work at 1/2 the price is tempting, but usually wasted money

BIG BLOCK CYLINDER HEAD COMPARISON ON CHEVY HIGH PERFORMANCE tested on the same 502 BBC
All flow figures on best ports, READ CAREFULLY AND NOTICE THE TQ STAYS AT ALMOST THE SAME PEAK due to similar compression and displacement but the HP varies with the flow rates as the rpms increase

AIR FLOW RESEARCH 325cc
$2485 ALUMINUM
Max hp 665
Max tq 593
intake
.200-158
.300-235
.400-298
.500-341
.600-370
.700-362
exhaust
.200-127
.300-188
.400-244
.500-268
.600-278
.700-285
the reason WHY the optionally fully CNC ported heads flow so well

brodix
RR OVAL 270cc port CNC chamber

.050 - 42 / 33 78.6
.100 - 77 / 65 84.4
.200 - 152 / 118 77.6
.300 - 224 / 147 65.6
.400 - 283 / 178 62.9
.500 - 318 / 205 64.5
.600 - 344 / 230 66.9
.700 - 347 / 248 71.5


AFR 265 CNC chamber

.050 - 39 / 32 82.1
.100 - 75 / 64 85.3
.200 - 168 / 144 85.7
.300 - 252 / 196 77.8
.400 - 307 / 232 75.6
.500 - 339 / 248 73.2
.600 - 350 / 254 72.6
.650 - 343 / 255 74.3


AFR 290

.100 - 74 / 63 85.1
.200 - 171 / 142 83.0
.300 - 249 / 200 80.3
.400 - 303 / 241 79.5
.500 - 342 / 259 75.7
.600 - 369 / 267 72.4
.650 - 365 / 270 74.0
.700 - 362 / 272 75.1

315afr1.jpg

315afr2.jpg

315afr3.jpg

gasketsh.png


if you have any engine and want too find the true compression you need to deal in verified fact, not assume what the manufacturers suggest is always correct.
you just cc the heads, combustion chamber volume, place the piston 1" down the bore and seal the rings gap around the pistons,
above the rings with moly grease or Vaseline and measure that volume and calculate what a bore diameter cylinder 1" tall would
contain, minus the volume you,ve measured, the piston dome took up.then calculate the true compression.


measure the piston deck height after the machined block has the rotating assembly test fitted
deckx.jpg

piston%20down%20in%20hole%20at%20TDC.jpg

peanutpl2.jpg



pdome2.jpg

pdome3.jpg

pdome1.jpg


read related linked info

http://garage.grumpysperformance.co...n-chamber-or-piston-dome-or-port-volume.2077/


http://garage.grumpysperformance.com/index.php?threads/ccing-my-heads.14187/#post-71989

http://garage.grumpysperformance.co...ng-combustion-chambers.2630/page-3#post-77963

pistonatbdc.jpg

pistonat%20tdc.jpg



BRODIX RACE RIGHT 294cc

$2393 per pair
Max hp-634
Max tq-582



intake
.200-141
.300-212
.400-269
.500-310
.600-332
.700-340
exhaust
.200-120
.300-159
.400-186
.500-212
.600-238
.700-262

Dart cnc pro1 335cc
$3654 per pair
Max hp660
Max tq598
intake
.200-154
.300-222
.400-280
.500-322
.600-355
.700-374
exhaust
.200-124
.300-175
.400-233
.500-272
.600-292
.700-311

EDELBROCK 454R 315cc
Aluminum # 60559 $1779 per pair
Max hp-616
Max tq-566

intake
.200-130
.300-198
.400-256
.500-287
.600-311
.700-326
exhaust
.200-122
.300-158
.400-185
.500-211
.600-236
.700-253


RACINF HEAD SEARVICE 320CC
Cast iron $2534 per pair
Max hp -638
Max tq-584

intake
.200-132
.300-199
.400-266
.500-319
.600-338
.700-356
exhaust
.200-113
.300-163
.400-197
.500-228
.600-259
.700-280

TRICKFLOW 320cc
Aluminum $2095cc


Max hp- 655
Max tq-587

intake
.200-146
.300-215
.400-271
.500-321
.600-353
.700-358
exhaust
.200-128
.300-171
.400-207
.500-243
.600-271
.700-290

world products 310cc MERLIN III
Aluminum
$2447 per pair
Max hp-631
Max tq-581

intake
.200-136
.300-200
.400-254
.500-297
.600-330
.700-345
exhaust
.200-105
.300-144
.400-173
.500-197
.600-217
.700-233

ID suggest you select from heads from these sources
Jegs; 800/345-4545; Jegs.com

Summit Racing; 800/230-3030; SummitRacing.com

Scoggin-Dickey Parts Center; 800/456-0211; ScogginDickey.com


TRICKFLOW
http://www.trickflow.com/egnsearch.asp? ... 4294867081
http://www.trickflow.com/customerservice
1-330-630-1555 • 1-888-841-6556

BRODIX
http://www.brodix.com/heads/heads.html
479.394.1075

DART
http://www.dartheads.com/products/cylinder-heads
Dart Machinery; 248/362-1188; DartHeads.com


AIR FLOW RESEARCH
http://www.airflowresearch.com/
toll free: 877-892-8844
tel: 661-257-8124

Patriot Performance
Patriot Performance; 888/462-8276; Patriot-Performance.com

TRJ
http://trjperformance.com/cylinder-heads-top-end-kits-components/complete-heads/

RHS
http://www.racingheadservice.com/rhs/cylinder-headshtml
Toll Free: 877-776-4323
Local: 901-259-1134

EDELBROCK
http://www.edelbrock.com/automotive_new ... main.shtml
Edelbrock; 310/781-2222; Edelbrock.com

BMP (world products)
http://www.theengineshop.com/products/cylinder-heads
http://www.theengineshop.com/produc...lum-heads-font/bmp-bbc-16-aluminum-heads.html
Tel: 631-737-0372
Fax: 631-737-0467

BUTLER PERFORMANCE
http://www.butlerperformance.com/products/cylinder_heads/cylinder_head_labor.html
866-762-7527

BLUE PRINT ENGINES
http://www.blueprintengines.com/ind...sb-chevy-aluminum-cylinder-heads-cnc-machined
1800-483-4263

PRO-FILER
https://www.profilerperformance.com/
937‐846‐1333
 
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http://www.airflowresearch.com/articles ... 1/A-P1.htm
http://www.airflowresearch.com/305bbc_rh.php
305cc-BBC-as-cast-graph.gif

http://www.racingheadservice.com/Inform ... -Heads.asp
PA-BBC-320cc.gif

PA-BBC-360cc.gif

http://www.airflowresearch.com/315bbc_rh.php
315cc-BBC-cnc-ported-graph.gif

http://www.airflowresearch.com/325bbc_rh.php
325cc-BBC-as-cast-graph.gif

http://www.airflowresearch.com/335bbc_rh.php
335cc-BBC-cnc-ported-graph.gif


http://www.airflowresearch.com/345bbc_rh.php
345cc-BBC-as-cast-graph.gif

http://www.airflowresearch.com/357bbc_rh.php

357cc-BBC-cnc-ported-graph.gif

http://garage.grumpysperformance.com/index.php?threads/aftermarket-heads-for-a-bbc.12316/
before you reach for your wallet, do some basic math and read a few dozen related links
http://www.wallaceracing.com/calcafhp.php

http://www.superchevy.com/how-to/en...-0902-chevy-engine-port-variations-measuring/

http://www.gmhpclub.com/performancecalculators.htm

http://garage.grumpysperformance.com/index.php?threads/port-speeds-and-area.333/#post-37705
USE THE CALCULATORS to match port size to intended rpm levels... but keep in mind valve lift and port flow limitations
http://www.wallaceracing.com/runnertorquecalc.php
http://www.wallaceracing.com/ca-calc.php
http://www.wallaceracing.com/area-under-curve.php
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php
http://www.circletrack.com/enginetech/1 ... ch_engine/



http://www.wallaceracing.com/calcafhp.php

http://hpwizard.com/engine-horsepower-calculator.html

http://www.hotrod.com/articles/airflow-research-cylinder-power/

http://www.powerperformancenews.com/tech-articles/cylinder-head-tech-airflow-vs-power/

http://www.calculator.net/engine-horsepower-calculator.html

http://www.calculatoredge.com/new/horsepower.htm
AFR OVAL PORT BBC FLOW NUMBERS
.050 - 39.4 / 32.2
.100 - 75.6 / 64.4
.200 - 168.0 / 144.5
.300 - 252.4 / 196.4
.400 - 307.3 / 232.5
.500 - 339.4 / 248.5
.600 - 350.7 / 254
.650 - 343.6 / 255
 
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trickflow bbc heads
http://www.summitracing.com/streetandst ... ABF6E40%7D
BMF
http://www.thebmfstore.com/SearchResults.asp?Cat=20

RFD
http://raceflowdevelopment.com/product/rfd-24-victor-pro-mc/
brodix
http://www.brodix.com/heads/headhunter.html

http://www.brodix.com/heads/headhunter.html

BBC Brodix Race Rite 270cc oval port flow numbers
just flowed a set of out of the box Brodix Race Rite oval port 270cc head. Here is the data

2.25/1.88 back cut on intake tulip exhaust valve
Throat
Long and Short runner 90%throat
Long and short runner bowl 91%
Short side long runner 2.93Csa
Short side short Runner 3.01CSA
Pinch Long runner 2.72CSA
Pinch Short Runner 2.74CSA

Flowed on a 4.310 bore

Intake Long
.1-77
.2-155
.3-219
.4-259
.5-292
.6-313
.7-320
.8-321
.9-316
1.0-311

Intake Short
.1-78
.2-148
.3-210
.4-252
.5-280
.6-305
.7-318
.8-327
.9-326
1.0-331

Exhaust no pipe
.1-59
.2-100
.3-128
.4-158
.5-183
.6-205
.7-225
.8-239
.9-252

bbc oval ports making 697hp
http://www.popularhotrodding.com/tech/0 ... /dyno.html

http://www.profilerperformance.com/bbc-heads-174.html

http://www.brodix.com/heads/jjbb.html

http://www.wengines.com/BBCweingartner.html

http://www.trickflow.com/partdetail.asp?part=TFS-4131B001&autoview=sku

http://static.trickflow.com/global/images/instructions/flow chart poweroval street bbc.pdf

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=796&p=1165#p1165

big block engines can be fun, as this photo shows
Mokan.jpg
 
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http://www.superchevy.com/technical/eng ... index.html
Big-Block Cylinder Heads - Head Trip, Part 2
Big-block heads for the spendthrift builder


all contributors: Mike Harrington




Oxymoron. Webster's dictionary defines this word as: "a combination of contradictory or incongruous words (as cruel kindness); broadly: something (as a concept) that is made up of contradictory or incongruous elements."

Besides "cruel kindness" here are some other examples: adult male, authentic replica, honest politician, jumbo shrimp, and military intelligence. For a long time, people would put the phrase "budget big-block" in there, too. But a little research proved there are very good values out there for those building a Rat with an eye on cost conservation.

In the last issue of Super Chevy, we went down the list of cylinder head manufacturers and got the latest dope from each company on their most popular off-the-shelf small-block cylinder heads. Mind you, we also informed each company that our aim was to search out their best "cost-conscious" cylinder heads. This month, we searched out those same parts for Chevy's fabled Rat motor. Yes, it's true that when one dives into the big-block waters, budget is a word that seldom comes to mind. Budgets, however, are like waist sizes-they vary from person to person. If only our wallets were akin to our waist sizes, what a wonderful world this would be.

It turns out that purchasing a set of BBC cylinder heads won't require you to sell a kidney on the black market; they're more affordable than you may think. When purchasing a set of cylinder heads, most DIYers prefer the out-of-the-box, preassembled units. Unless you're running some insanely wild cam, the springs and valves in the preassembled heads are capable of delivering some great performance numbers over the OE-spec heads. In no particular order, here are the companies we contacted and the information they provided.




World Products
(631) 981-1918
http://www.worldcastings.com

Merlin Cast Iron 269cc BBC Cylinder Head, Merlin III Cast Iron 320cc BBC Cylinder Head

World has a couple of BB heads that are perfect for the budget builder. The first one is the assembled Merlin oval port cast iron head, with a 269cc intake volume, a 119cc combustion chamber, 2.300x1.88 valves and 11/32 guides. Out of the box these heads run about $720. The next step up is the Merlin III. This head features a 320cc intake chamber and opens up to a 345cc intake chamber. The combustion chamber, valves and guides are the same as the Merlin. An assembled set of the 345cc heads will run about $1,459.




Racing Head Service
(877) 766-4323
http://www.racingheadservice.com

Pro Action Cast Iron 320cc Cylinder Head, 360cc BBC Cylinder Head

Racing Head Service knocked one out with its Pro Action cast iron heads. The Pro Action heads come in a 320cc and 360cc intake runner. Both heads feature a 119cc combustion chamber with intake valves (with hardened seats) that measure 2.250 and exhaust valves that measure 1.880. A pair of assembled 360cc heads built for a hydraulic roller cam runs about $1,810. The same set built for a mechanical roller runs about $2,064.




Summit Racing Equipment
(800) 230-3030
http://www.summitracing.com

Square Port Iron 308cc BBC Cylinder Head

Millions have ordered parts from Summit Racing, but some may not be familiar with the fact that Summit also offers its own line of cylinder heads for the Chevy big-block. Summit has set of cast-iron heads that are ready to run from the moment you open the box. The Summit square port iron heads feature a 308cc intake runner with a 119cc combustion chamber, a 2.250 intake valve and a 1.880 exhaust valve with hardened seats. A pair of assembled heads runs about $1,291.

Big-Block Cylinder Heads - Head Trip, Part 2





Brodix
(479) 394-1075
http://www.brodix.com

Race Rite BB-R 294cc, BB-O 270cc BBC Cylinder Head

Brodix has a direct replacement for stock cast-iron heads. These heads from its Race Rite series are made from cast aluminum and are available in rectangular or oval port castings. Brodix has also designed the Race Rite heads to work directly with the stock pistons and intake manifold. The Race Rite heads come in two available sizes: the BB-R comes with a 294cc intake port while the BB-O comes with a 270cc intake port. Both heads have a 119cc combustion chamber, a 2.250 intake valve, and a 1.880 exhaust valve. An out-of-the-box assembled pair of the Race Rite heads runs approximately $1,939.




Holley
(270) 782-2800
http://www.holley.com

Aluminum Oval Port 261cc Intake BBC Cylinder Head

Holley gets it done with a pair of aluminum oval port heads that have been CNC-machined. They are made for engines made from 1965 to 1975 with EGR (pn 300-556), and without EGR (pn 300-554). The Holley heads have 261cc intake and 110cc combustion chamber that are designed for low compression pump gas use. These heads come with a 2.19 and 1.88 intake and exhaust valves and stock location exhaust ports. An assembled set of heads will run about $2,200.




Jegs
(800) 345-4545
http://www.jegs.com

"J" Series Cast Aluminum 310cc BBC Cylinder Head

Jegs High Performance not only sells just about any performance part you can think of, it also sells its own performance Rat heads. Jegs "J" series of BBC heads are cast aluminum and CNC-machined for a precise fit. These square port aluminum heads feature 310cc intake runners, as-cast 119cc combustion chambers and raised exhaust ports (.625-inch). Jegs uses longer valves so you will need to check pushrod length. A pair of assembled "J" series heads retails at $1,779 (base price).




Air Flow Research
(877) 892-8844
http://www.airflowresearch.com

Magnum 325cc BBC Cylinder Head

AFR's Magnum heads are available with a variety of upgrades, ranging from intake port sizes starting at 305 cc all the way to 357 cc. The upgrades are almost too numerous to list, so we'll take a look at the as-cast, CNC bowl-blended, aluminum Magnum 325cc intake port head. This particular head comes with the standard 119cc combustion chambers, 2.250 intake valves and 1.880 exhaust valves. Should you desire a fully CNC'd set of heads from AFR, all you have to do is ask. A pair of the 325cc heads usually retails for around $2,485.




Edelbrock
(800) 416-8628
http://www.edelbrock.com

Oval Port Aluminum Performer 290cc BBC Cylinder Head

The Edelbrock Performer series of cylinder heads really needs no introduction. The oval port aluminum Performer heads feature 290cc intake ports and 110cc combustion chambers with 2.19 and 1.88 intake and exhaust valves. The Performer is a great streetable head and retails for about $1,920.




GM Performance Parts
(877) 892-8844
http://www.airflowresearch.com

Oval Port Aluminum 290cc BBC Cylinder Head

GMPP has a pair of great aluminum oval port heads featuring 290cc intake runners and 110cc combustion chambers and 2.250 and 1.880 intake and exhaust valves. The exhaust ports are in the stock location so there's no need to mess around with new headers. Out of the box, an assembled pair of these heads will run about $1,920.

Trick Flow Specialties
http://www.trickflow.com
(330) 630-1555

Oval Port Aluminum 280cc BBC Cylinder head

Trick Flow also has a few big-block cylinder heads, but we will focus on its premier budget cylinder head, the oval port aluminum version. It helps build great low- to mid-range horsepower. These heads have 280cc intake runners and 113cc combustion chambers. An assembled set of these heads runs approximately $1,925.
trickf1.png

trickf2.png



Powerhouse Engine Components
(661) 861-0167
http://www.enginekits.com

Cast Aluminum 320cc BBC Cylinder Head

Powerhouse surprised us with a set of cast aluminum big-block heads that feature 320cc intake runners and 115cc combustion chambers. The intake and exhaust valves measure in at 2.25 and 1.88 respectively. These heads are assembled for hydraulic flat tapped lifters, and upgrades are available, so give them a call. An assembled set from Powerhouse will cost $1199.

Going Back To Last Month
Editor's note: Due to circumstances beyond our control, the following text and photos from part 1 of this story (which dealt with small-block cylinder heads) were left out of the May issue. Here is the conclusion of Head Trip, Part 1, in its entirety. We apologize for the error.

http://www.hotrod.com/how-to/engine/0906phr-10-questions-chevy-big-block/
portvl.png

portvl1.png


portvl2.jpg



JEGS
(877) 892-8844
(800) 345-4545
http://www.jegs.com

High-flow 197cc Aluminum SBC Cylinder Heads, 220cc Aluminum SBC Cylinder Heads

These heads are designed to support 425-500 hp in 350-406ci engines. They feature large, high quality stainless steel 2.055-inch intake and 1.600 exhaust valves. According to Jegs, the intake port cross-section was designed for good mid-range power. The heads work well with cams featuring duration of 210-240? @ .050 inches. 197cc Intake runners, 1.440-inch springs, 1.875-inch installed height, 130-pound seat pressure, 3/8-inch studs, and 5/16-inch guideplates included; 2.055-inch intake/1.600-inch exhaust. Cost: $1,118 (197cc head).

Jegs also has a 220cc high-flowing aluminum head. It features 220cc intake runners, 240 pounds seat pressure, .680-inch maximum lift, 64cc CNC-machined combustion chambers with angle plug design, 10? locks, steel retainers and bronze guides, 2.100-inch intake and 1.600-inch exhaust stainless steel valves, 7/16-inch rocker studs and 5/16-inch guide plates. Cost: $1,372 (220cc head).




Summit Racing Equipment
(800) 230-3030
http://www.summitracing.com

Summit 170cc Cast-iron Vortec SBC Cylinder Head, Summit Street & Strip 200cc Aluminum SBC Cylinder Head

Are you looking for a good set of heads to up the performance factor of your Vortec engine? Summit Performance Vortec cylinder heads have what it takes to get the job done. Featuring wide-open intake runners, efficient combustion chambers, and a high-performance valve job, these heads deliver plenty of power-building airflow. Made from superior iron alloy, these heads come ready-to-run for improved performance straight out of the box.

Specs: cast iron cylinder head material; combustion chamber volume 67cc; intake runner volume 170cc; intake valve diameter 1.940 inches; exhaust valve diameter 1.500 inches; maximum valve lift 0.520 inches; outside diameter of outer spring 1.250 inches. Cost: $649 (both 170cc and 200cc).




Trick Flow Specialties
(330) 630-1555
http://www.trickflow.com

Trick Flow 195cc Aluminum SBC Cylinder Head

Dyno-tested on a 383ci engine, Trick Flow's 64cc 23? 195cc aluminum cylinder heads made 460 hp and 451 lb-ft of torque-40 more horsepower and 11 lb-ft more torque than the same engine with GM L98 Corvette heads. The 195 heads are a direct fit, high-performance replacement for most original equipment factory heads, and accept most factory accessories. They feature a choice of 62cc as-cast, or 64cc and 72cc CNC-profiled combustion chambers, 2.02/1.60 stainless steel valves, hardened exhaust valve seats for unleaded gas, and 195cc intake ports with a high-velocity, small cross-section design to promote low-rpm torque without sacrificing higher-rpm horsepower. The heads are available with three spring sizes: 1.250-inch single for cams up to .480-inch lift; 1.470-inch single for cams up to .540-inch lift; and 1.460-inch dual for cams up to .600-inch lift. They come fully assembled with valves, valve springs, locks, retainers, rocker arm studs, and guideplates. The heads are 50-state emissions-legal under CARB E.O. number D-369-4. Cost: approximately $1,249 (assembled).




Edelbrock
(310) 781-2222
http://www.Edelbrock.com

Performer 170cc Aluminum SBC Cylinder heads

The key to any successful engine buildup lies in using parts that work together, and Performer RPM cylinder heads are designed specifically for street-driven cars with moderate compression and pump gas. The high velocity 170cc intake ports produce outstanding throttle response and torque, with enough air flow to produce over 400 hp when used with matching a Performer RPM manifold, cam, and carb. The Performer RPM head #60899 comes fully assembled and ready to run with 2.02/1.60-inch stainless steel valves; valve springs rated up to .575-inch lift; 64cc combustion chambers; 60cc exhaust ports; and straight spark plugs for use with standard exhaust headers. Performer RPM small-block Chevy heads are also available bare, or complete with 70cc combustion chambers and angled spark plugs. Like all Edelbrock heads, they're cast at the Edelbrock Foundry from 356-T6 aluminum and incorporate Heli-Coil inserts in the rocker stud and exhaust bolt holes for strength and durability. Cost: The MSRP is $1,648, but check with your local Edelbrock dealer
for more info.

your engines torque curve is more the result of displacement, compression,ratio,selected cam timing and both header design (scavenging) and intake design (SINGLE vs DUAL PLANE ETC.)than just port cross sectional area alone, and if your wearing valve guides the valve train geometry and clearances, and lubrication system, and the oil used in it, and your valve spring rates and seals need to be carefully checked and a rocker stud girdle and roller rockers used
and port cross sectional area and flow numbers have a larger effect than port shape alone
naturally you'll need to match the port cross sectional area, length, and plenum to the intended displacement and rpm band, and cam timing, but just assuming a swap from rectangular port to oval will always result in more torque will not always be true over the whole power band, especially if the rest of the combos designed for a totally different rpm band than the heads you've selected.
tweaks like tuned merge collectors, and slightly different cam timing and intake swaps can get a great deal more of the torque potential from a slightly different port size,and there are calculators you can use to find a limited selection of choices,in header length, diam., collector, intake port length and cross section and runner length, plenum size, cam timing and valve size to look thru.. too narrow your search for the best match to your application vs just guessing and swapping parts till you think you've got it correct

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=333

http://www.hughesengines.com/TechArticles/1headflowchartscomparisons.php
 
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WHEN your talking about a car that's expected to be street driven, and geared and cammed to drive on the street, with pump gas,the larger OVAL port heads will generally produce better hp/tq than a 320cc rectangular port head on a 427 BBC, provided the compression ratio and cam and intake are carefully matched

even the stock oval ports CAN in some cases work well
ovalportlong.jpg

ovalportlong1.jpg

http://maliburacing.com/patrick_budd_article.htm

http://www.brodix.com/heads/raceritebb.html

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

http://www.summitracing.com/parts/TFS-41310001/

It should be obvious that comparing edelbrock oval ports, or mildly reworked stock heads to AFR 305-357cc heads, and an engine with a hydraulic roller cam, is hardly a valid comparison, to an engine with a solid roller , or flat tappet cam, using higher compression and the better rectangular port heads, thats designed to run a couple of thousand rpm higher on average.
as Im sure you are aware
now I have built a bunch of big blocks and its not just the heads selected that matters, and you generally try to match the port cross sectional area to the intended displacement and cam timing, but, you can compensate for some minor mis-matches in port size thru the wise selection of other components, but almost all rectangle port heads are designed for the upper rpm band and solid lifter cams that allow them to breath, most but not all oval ports are designed for mid rpm range torque combos
the 290cc and larger oval ports are generally designed to breath far better than the stock 253cc heads most guys think of when they think oval port heads
now IM sure not going to tell you that a properly built big block with oval port heads will destroy a properly built big block with rectangle port heads , but if you start limiting the rpm potential with hydraulic cams, want to drive the car in traffic and expect to drive the combo on the street on trips they can provide a very valid option

bbc oval ports making 697hp
http://www.popularhotrodding.com/tech/0704phr_chevy_big_block/dyno.html

http://www.profilerperformance.com/bbc-heads-174.html

http://www.brodix.com/heads/jjbb.html

http://www.trickflow.com/partdetail.asp?part=TFS-4131B001&autoview=sku

http://static.trickflow.com/global/images/instructions/flow chart poweroval street bbc.pdf

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=796&p=1165#p1165


BTW if your looking into aftermarket performance cylinder heads for the BIG BLOCK CHEVY, the blocks have different coolant passage lay outs, and require matched heads and head gaskets , but check with the manufacturer of the cylinder heads, many of the better aftermarket big block heads have been modified with a larger sealing surface areas and relocated coolant passage locations and coolant passage shapes so that they can be used with any and all the generations of the big block blocks, if the correct gaskets are used, simply because the manufacturers found that to be far easier than stocking several different castings for basically similar applications




  1. 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

no, if you have any engine and want too find the true compression you need to deal in verified fact, not assume what the manufacturers suggest is always correct.
you just cc the heads, combustion chamber volume, place the piston 1" down the bore and seal the rings gap around the pistons,
above the rings with moly grease or Vaseline and measure that volume and calculate what a bore diameter cylinder 1" tall would
contain, minus the volume you,ve measured, the piston dome took up.then calculate the true compression.

measure the piston deck height after the machined block has the rotating assembly test fitted
deckx.jpg

piston%20down%20in%20hole%20at%20TDC.jpg

peanutpl2.jpg



pdome2.jpg

pdome3.jpg

pdome1.jpg


read related linked info

http://garage.grumpysperformance.co...n-chamber-or-piston-dome-or-port-volume.2077/


http://garage.grumpysperformance.com/index.php?threads/ccing-my-heads.14187/#post-71989

http://garage.grumpysperformance.co...ng-combustion-chambers.2630/page-3#post-77963
heres two of the few side-by-side closed chamber vs open chamber pictures I have,
mortec
http://www.mortec.com/bbc.htm

and several other sites list your combustion chambers at 98cc, and most closed chamber heads I see average around 100-107cc so its likely your have had mods


WELL WORTH READING THRU

http://victorylibrary.com/mopar/chamber-tech-c.htm

http://www.corvettefever.com/techarticl ... index.html


typical tool used to bevel the combustion chambers
http://www.goodson.com/store/templat...6e31d1882c7e8e
http://www.goodson.com/store/templat...6e31d1882c7e8e


MORE OPTIONS

http://www.trickflow.com/partdetail.asp ... toview=sku

http://www.profilerperformance.com/bbc-heads-174.html

http://www.airflowresearch.com/index.php?cPath=68_111

http://www.jegs.com/p/Brodix/Brodix-Rac ... 9/10002/-1

http://www.racingheadservice.com/Cylind ... 11-02.aspx

http://www.edelbrock.com/automotive_new ... mer1.shtml
100cc heads

http://www.worldcastings.com/products/m ... heads.html
80cc heads


AFR 290 full cnc 28" 4.530 & 4.310 bore no pipe clay radius
lift - - 4.530 / 4.310 - ex
100 - 74.70 - 72.90 --- 63.70
200 - 171.5 - 163.3 --- 142.4
300 - 249.4 - 237.0 --- 200.9
400 - 303.4 - 285.9 --- 241.0
500 - 342.4 - 324.9 --- 259.8
600 - 369.4 - 352.7 --- 267.5
650 - 365.7 - 361.8 --- 270.0
700 - 362.1 - 370.9 --- 272.4

And here is a couple of other heads on my bench for comparison

Perf RPM #60459 290cc Intake port 2.19x1.88 110cc chamber
.100 - 73/ 64
.200 - 148/119
.300 - 218/149
.400 - 268/179
.500 - 304/207
.600 - 317/229
.700 - 319/245

RR OVAL 270cc port
100 - 77/65
200 - 152/118
300 - 224/147
400 - 283/178
500 - 318/205
600 - 344/230
700 - 347/248

AFR 315 CNC
4.530" ===========4.310" bore
.100 - 78/69 ========78.1
.200 - 164/142.5 =====162.3
.300 - 247/198 ======239.5
.400 - 309/240====== 290
.500 - 350/267 ======334.4
.600 - 375/280 ======358.3
.700 - 383/283 ======374
 
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NOW if youve got money to burn maybe you want some killer big block heads, trust me! racing engine technology ALWAYS has something new under development that costs far more cash than you can easily come up with and potentially makes all your current components TOTALLY PATHETIC, you can very easily drop $30K-$80K into exotic engine components if you had bill gates check book

http://www.mbellc.com/index.php/24d-conv401-bbc
mbe-24-degree-conventional-401-BBC.png


http://www.mbellc.com/index.php/11d-big-chief
mbe-11-degree-big-chief-standard.png



http://www.mbellc.com/index.php/18d-conv-b-b310-cc
mbe-18-degree-conventional-big-block-310-cc.png


http://www.brodix.com/heads/pb1200.php
pb1200intakeinfo.jpg


http://www.brodix.com/heads/pb1800.php
PB-1803-KC-intake2.jpg


THERE ARE EVEN HEADS WITH PORTS AND VALVES SO LARGE THEY REQUIRE A CUSTOM BLOCK WITH A LARGER CRANK AND BORE SPACING

http://www.cnblocks.com/5300BBC/5300BBC.html

21096347-221-Sonnys-hemi-heads.jpg




21097950-968-undefined.jpg


5301-reverse-adjusted-3.jpg


5301-adjusted-2.jpg


http://www.raceflowdevelopment.com/RFD- ... dartBC.htm

rfd1118.jpg
 
a back-to-back flow comparison comparing factory "advertised" numbers with actual flow numbers from a SF600 with a FlowCom and Audi swirl meter, 4.500 bore fixture, and see just what the truth is.
Heads are a good comparison for competitors:
Dart Pro1 310 as cast, bare, from Dart
AFR 305 as cast, assembled from AFR

Dart 310, valve job from Dart, REV 2.25 intake no backcut, REV 1.88 Inconel ex (tulip style valve), advertised intake @ 28" .800 (all they give you from Dart) 369 cfm.

Truth:
Left/right/ex

.2 140/141/111
.3 207/207/151
.4 271/271/192
.5 322/312/227
.6 351/329/254
.7 365/329/271
.8 341/335/281

The left port is not a mis-print. Very disappointing.

Next: AFR 305 as-cast, assembled from AFR with their valves, 2.25 intake with backcut (angle unknown) AFR 1.88 exhaust.

AFR as-cast advertised:
right/ex

.2 154/131
.3 223/176
.4 287/219
.5 335/251
.6 363/276
.7---------

Truth:

right/left/ex

.2 146/143/109
.3 209/210/144
.4 268/276/185
.5 324/327/223
.6 366/336/250
.7 361/343/262
.8 ---/345/271

The bowls are nicely CNC blended but transition from the seat to the chamber is terrible. The exhaust port I believe suffers far worse because of this than the intake.

http://www.superchevy.com/how-to/engine ... w-testing/

http://www.superchevy.com/how-to/engine ... omparison/
bbcbooklh.jpg

TRICKFLOW
http://www.trickflow.com/egnsearch.asp? ... 4294867081
http://www.trickflow.com/customerservice
1-330-630-1555 • 1-888-841-6556

BRODIX
http://www.brodix.com/heads/heads.html
479.394.1075

DART
http://www.dartheads.com/products/cylinder-heads
Dart Machinery; 248/362-1188; DartHeads.com


AIR FLOW RESEARCH
http://www.airflowresearch.com/
toll free: 877-892-8844
tel: 661-257-8124

Patriot Performance
Patriot Performance; 888/462-8276; Patriot-Performance.com

TRJ
http://trjperformance.com/cylinder-heads-top-end-kits-components/complete-heads/

RHS
http://www.racingheadservice.com/rhs/cylinder-headshtml
Toll Free: 877-776-4323
Local: 901-259-1134

EDELBROCK
http://www.edelbrock.com/automotive_new ... main.shtml
Edelbrock; 310/781-2222; Edelbrock.com

BMP (world products)
http://www.theengineshop.com/products/cylinder-heads
Tel: 631-737-0372
Fax: 631-737-0467

BUTLER PERFORMANCE
http://www.butlerperformance.com/products/cylinder_heads/cylinder_head_labor.html
866-762-7527

BLUE PRINT ENGINES
http://www.blueprintengines.com/ind...sb-chevy-aluminum-cylinder-heads-cnc-machined
1800-483-4263

TRJ
http://trjperformance.com/cylinder-heads-top-end-kits-components/complete-heads/

PRO-FILER
https://www.profilerperformance.com/
937‐846‐1333

O.M.E. BBC Heads


330864.....68-84...oval...OPEN...396, 402, 366T,
427T, 454 Truck
330865.....68-84...oval...OPEN...396, 402, 366T,
427T, 454 Truck
330866.....68-78...oval...OPEN...366T, 427T
330867.....68-73...oval...OPEN...427T
336765.....68-78...oval...OPEN...427T
336768.....73-76...oval...OPEN...427T
336781.....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports
343771.....68-86...oval...OPEN...366T, 427T, 454
343772.....68-86...oval...OPEN...366T, 427T, 454
343783.....70-76...oval...OPEN...454 Truck
346236.....75-87...oval...OPEN...454, 120cc chamber, 225/116cc ports
352625.....70-76...oval...OPEN...454 Truck
353049.....73-84...oval...OPEN...454, 122cc chamber, 255/119cc ports
366765.....74-78...oval...OPEN...427T
473328.....68-69...oval...OPEN...366T
3856206....65-66...oval..CLOSED..396, 97cc chamber
3856208....65......rect..CLOSED..396/425hp, 109cc chamber
396/375hp "Z-16" Chevelle
3856213....66-82...oval..CLOSED..366T, 427T
3856260....68......oval..CLOSED..396 Truck
3872702....65-66...oval..CLOSED..396, 427, 98cc chamber
3873858....65-67...rect..CLOSED..396, 427, 109cc chamber
3876875....77-85...oval...OPEN...427T
3904390....67......oval..CLOSED..396, 427, 98cc chamber
3904391....67......rect..CLOSED..396, 427, 107cc chamber
3904392....67......rect..CLOSED..427, Aluminum, L88, L89, 107cc chamber
3904393....68-76...oval...OPEN...366T
3908952....67......oval...OPEN...427, "M.Truck", Marine
3909802....67......oval..CLOSED..396, 427, 101cc chamber
3917215....67-68...oval..CLOSED..396, 427, 101cc chamber
3917219....68-85...oval...OPEN...366T, 427T
3919840....67-69...rect..CLOSED..396, 427, 107cc chamber
3919842....68-69...rect..CLOSED..396, 427, Aluminum L88, L89, 107cc chamber
3931063....68-69...oval..CLOSED..396, 402, 427, 101cc chamber
3933148....69-84...oval...OPEN...'69 396/265hp, 366T, 427T, 112cc chamber
3933149....68-76...oval...OPEN...427T, 122cc chamber
3935401....68-76...oval...OPEN...427T
3946074....69&71...rect...OPEN...'69 427 L88, ZL1, Aluminum, 118cc chamber
'71 454 LS6, "round exhaust port"
3964290....69-70...oval..CLOSED..396, 402, 427, 454, 101cc chamber
Large or small hex spark
plugs used
3964291....69-72...rect..CLOSED..396, 402, 427, 454, 109cc chamber, Large or small hex spark plugs used, crate motor usage in years after 1970.
3965198....68-69...oval..CLOSED..396 Truck
3975950....68-70...oval...OPEN...396, 402 Truck, 366T, 427T
3986133....68-85...oval...OPEN...366T, 427T, 454 Truck
3986135....69-73...oval...OPEN...366T, 427T
3986136....68-84...oval...OPEN...366T, 427T, 454 Truck
3993820....71......oval...OPEN...402, 113cc chamber, 255/114 ports
3993820....71-84...oval...OPEN...454 Passenger and Trucks, 113cc chamber, 255/114 ports
3994026....71......rect...OPEN...454 LS6, 118cc chamber
3999241....72......oval...OPEN...402, 454, 113cc chamber

6272292....70-78...oval...OPEN...402, 454
6272990....70-up...rect...OPEN...454 service replacement, used on some MKIV crate engines, 118cc chamber
10045427...........rect..........Pontiac/Chevy Aluminum, 91cc chamber
Large Port, race
10049875...........rect..........Pontiac/Chevy Aluminum
Small port, race
10051128...........rect..........Bowtie, Aluminum 72cc chambers
Symmetrical ports
10051129...........rect..........Bowtie, Aluminum "raw"
casting, Symmetrical ports
10052902...........oval...OPEN...MkIV, 427T
10101140...91-up...oval..CLOSED..Gen.V 366T, 427T
10114156...91-up...oval...OPEN...Gen.V & VI 454, 118cc chamber
10141279...96-up...oval..CLOSED.."Vortec 7400", 100cc chambers
10487052...77-90...oval...OPEN...366T
12363391...96-up...oval...OPEN...Bowtie, Aluminum, Signature
Series, fits MKIV, Gen.V, Gen.VI, 110cc chamber
12363401...96-up...rect...OPEN...Bowtie, Aluminum, Signature
Series, fits MKIV, Gen.V, Gen.VI, 118cc chamber
12558162...01-up...oval..CLOSED..Gen.VII,"Vortec 8100", 8.1L, 496, truck
12560241...98-up...oval..CLOSED.."Vortec 7400", 100cc chambers
12562932...91-95...oval...OPEN...Gen.V, truck crate motor, 118cc chambers
12562933...91-95...oval...OPEN...Gen.V, 118cc chambers
12562934...00-up...rect...OPEN...Gen.VI 502 Marine
14011077...69-up...rect...OPEN...Aluminum, fits MKIV, "C-port"
118cc chamber, also sold as a "solid" head
14044861...84-96...rect..........Bowtie, Aluminum, MkIV,
"raised runners", 1st design, 105cc chamber
14044861...96-up...rect..........Bowtie, Aluminum, Signature
Series, fits MKIV, Gen.V, Gen.VI
"raised runners", 2nd design, 115cc chamber
14044861...84-96...rect..........Bowtie, Aluminum, MkIV
"raw" casting of "861" MKIV
1st design
14081045...78-87...oval...OPEN...454
14081052...85-87...oval...OPEN...366T, 427T, 454 Truck, Marked "HiPerf"
14092359...86-90...oval...OPEN...366T, 427T, Marked "HiPerf"
14092360...86-90...oval...OPEN...454 Truck, "peanut" round ports
14096188...70-71...rect...OPEN...454 service replacement, also used on later Mark IV LS-6, LS-7 and 454 HO crate motors, 116cc chamber
14097088...91-up...rect...OPEN...Gen.V 454/502 HO, 118cc chamber
24502585...97......rect..........Olds/Chevy, DRCE 2,
Pro Stock aluminum, for blocks w/4.900" bore spacing
25534404...04......rect..........Olds/Chevy, DRCE 3, Pro Stock, aluminum, for blocks with 4.900" bore spacing

T = Tall deck
Oval includes both "peanut" (also called "round") ports and large oval ports
 
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http://www.dragzine.com/tech-stories/en ... nder-2000/

BUDGET HEADS


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 (1996-2000)


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)


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)
 
http://www.dragzine.com/tech-stories/en ... nder-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)


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)


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)


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 (1996-200

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)


(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)
 
http://www.rehermorrison.com/rmComponents.htm
This aluminum head can only be purchased from Reher-Morrison. It is a true proprietary cylinder head design exclusive to Reher-Morrison. It is like no other spread port head on the market. Works great with Nitrous! This is not the same as any other 12 degree on the market.

The Raptor is a break-through in BBC spread port cylinder head development. Raptor cylinder heads are designed by Reher-Morrison and contain features and benefits not found in any other spread port heads. These are cutting-edge Pro Stock style intake ports utilizing High velocity/Wet flow technology found in no other Big Block Chevy head on the market today! With over two years in development Reher-Morrison has created a cylinder head capable of producing more power in a Big Block Chevy than was previously possible. These heads are featured in the RMRE Super Series 12° 565, 588, 622, and 665.

The Raptor components include:

Reher-Morrison 12° Raptor BBC Cylinder Heads
1.645" O.D. Triple Pacaloy Springs
10° Manley Titanium Retainers
10° Heat-Treated Comp Cams Valve Locks
Manley 2.450"/1.850" Custom Titanium Valves
423+cfm @.500"/525cfm @.800"/535cfm @.900"/540cfm @1"
Flows more air per valve size than any other spread port cylinder head!
65cc Chambers 465cc Intake Ports
Variable valve sizes available for specific applications, 2.450"/1.850" standard
Uses standard BBC spread port cylinder head components, less costly to update!
Faster throttle response when using a throttle stop
Broader horsepower and torque curve than other BBC spread port cylinder heads
More potential horsepower per dollar than any other BBC cylinder head
Provides the next level of BBC performance for nitrous, blown or naturally aspirated applications

Available exclusively from Reher-Morrison!

Price: $6,895.00 - Call to order!

http://www.popularhotrodding.com/tech/0 ... to_06.html

http://www.enginebuildermag.com/Article ... gines.aspx

http://www.enginebuildermag.com/Article ... pdate.aspx

http://www.aera.org/engine-professional ... echnology/

http://www.precisionenginetech.com/tech ... ns-part-2/
 
AFR new 300 oval port heads

AIR FLOW RESEARCH has come out with a new large oval port head thats sized to match the street/strip use of a 477-509 displacement big block to maximize mid and upper mid rpm torque and power, this should be a good choice on a street driven performance application.

afr300oval.jpg

Chris Sperling who handles most of our IT/catalog/website is at IMIS working the tradeshow so Im having a hard time getting the PDF of the flowcurve we have printed in our 2013 catalog so in the meantime I will just post the numbers here and update this thread at a later date with the better looking "official" flow chart when I have access to that....either way its the information you guys are in search of and justifiably so

These figures are taken on a "real world" 4.310 bore fixture (they would have looked even stronger on a 4.500 or 4.600 bore) and the exhaust is tested with a curved 2" pipe that very much resembles a header (the catalog shows 1.875 which is incorrect....just an FYI). Intake port flowed with a proper fitting radius plate of course (3/4 radius).

Intake Flow

.200....165
.300....240
.400....296
.500....340
.600....378
.650....385
.700....388

Exhaust Flow

.200....135
.300....190
.400....234
.500....265
.600....280
.650....288
.700....295


Note these numbers are conservative if anything....my prototype goes almost 10 CFM more than this and we wanted to sandbag a little to cover tool life and stacking of tolerances (a few thou) on the CNC machines. Even CNC machines can produce slightly different results from head to head / machine to machine, but if you stay on top of tool life and fixture locations, the repeatability is very impressive. To be honest, it's an art form we are in a continuous state of improving (something we tend to hyper focus on) and we have made huge strides in that aspect of our business in the 11 or so years I have been here to witness and be part of. What only a few years ago might have been "acceptable" now isn't....we constantly try to push ourselves to higher standards and the quality of what we ship has never looked better.

Anyway....when I have a chance I will grab some pics of the 300 Roval when the heads from IMIS come back and at some point update this post with the "official" AFR flow chart from the catalog but if you have seen an AFR 290 up close and personal it looks extremely similar with the most glaring difference the slight increase in valve size from 2.250 to 2.300

Regards,
Tony
 
http://www.dragzine.com/news/new-produc ... der-heads/

Edelbrock’s New RPM Xtreme Big Block Chevy Cylinder Heads
by Ian McBride on June 3, 2010


Edelbrock has developed a new set of cylinder heads for 427-572 cid Big Block Chevy engines named ‘RPM Xtreme Cylinder Heads.’ The heads produce flow numbers competitive with the Victor series race heads, but they still maintain compatibility with off-the-shelve components. The rectangular port heads are available with a larger chamber for forced induction and pump gas motors.

Official Release:

The new Edelbrock RPM Xtreme Cylinder Heads for 427 – 572 cid Big Block Chevy engines strive to provide race level performance in a streetable design envelope. CNC machined runners and combustion chambers achieve flow numbers nearly on par with the Victor series professional race head, while maintaining compatibility with off-the-shelf or even stock components including headers, pistons and rocker arms. The deck has been rolled 1.5° to improve the intake valve angle and consequently port velocity, while ensuring that the 2.25″ (oval) / 2.30″ (rect.) intake and 1.88″ exhaust valves will still clear the factory valve reliefs. The exhaust flange has been raised less than 1/8″ to improve flow around the short turn without causing conflicts with off-the-shelf 2″ primary tube headers designed to work with stock heads. The 300cc (oval) / 325cc (rect.) intake ports and 110cc chamber volumes will ensure that the performance potential of these heads is sufficient for nearly any street driven application. The rectangular port heads are even available with a larger 118cc chamber to support forced induction and pump gas friendly compression ratios.

Rectangle port RPM XT heads #51559 testing on a 555 cubic inch big-block Chevy with 10.0:1 compression, hydraulic roller camshaft [248°/256° duration @ .050] and Edelbrock RPM XT EFI system produced 697 HP and 643 lbs./ft. of torque.

Edelbrock aluminum cylinder heads are sand cast at our private foundry in San Jacinto, CA and are hand assembled at our Torrance, CA headquarters. They carry a one year warranty against any manufacturer defects, and are sold complete with valves, springs and guides pre-installed. Installation is the same as factory cylinder heads, making this an easy bolt-on upgrade with results you will feel on every pull.

Features Include:

CNC ported combustion chambers, intake and exhaust runners improve air-flow and performance
Fully CNC machined combustion chambers
25-degree valve angle
5/8″ thick deck for extreme durability
Outstanding flow; up to 385 cfm (rectangle port) and up to 356 cfm (oval port)
RPM XT heads accept most stock port location exhaust headers
 
http://www.superchevy.com/technical/eng ... ewall.html

Ask a big-block enthusiast what they need to make 600 hp and chances are they will point to some sort of rectangular-port head. No one in their right mind would select an oval-port head to make that kind of power, let alone one with a diminutive 265cc intake port, right? Well, big-block fans, times have changed and so has that well-defined line between the pedestrian oval-port and rectangular-port performance heads.

Back in the day, all the factory high-performance Rat motors were sporting rectangular-port heads and the street/strip crowd followed suit. But that was then and this is now. The aftermarket has stepped up in a big way and produced oval-port heads that not only out-flow any factory rectangular-port version, but do so while dramatically reducing port volume. The combination of more flow and less port volume makes these oval-port heads a much better choice for your street/strip motor than their rectangular-port counterparts. For motors up to and even beyond 600 hp, especially small-displacement big-blocks (under 500 inches), the hot setup today is more than likely an aftermarket oval-port.

With oval-port heads taking the street/strip market by storm, we decided it was a good idea to take a long hard look at them and thoroughly check out the performance potential. This meant gathering a number of different oval-port cylinder heads and putting them through their paces, both on the flow bench and the engine dyno.

First up, we needed a suitable test motor. We decided on a 0.060-over 454 equipped with a forged crank and forged rods from Procomp Electronics matched to a set of forged pistons from Probe Racing. The pistons feature an 18cc dome to help provide a streetable static compression over 10.0:1 with the 110cc chambers employed on a couple of the oval-port heads.

Many of these heads offered combustion chamber volumes below the 120cc range used on most rectangular-port heads. The smaller chamber (relative to factory rec-port heads) improved power by increasing the static compression--always a plus. The test motor also featured a healthy hydraulic roller cam in the form of an XR300HR from Comp Cams. It a 0.560/0.580 lift split, a 248/254 duration split, and a 110-degree LSA. All testing was run with an Edelbrock Victor Jr. intake fed by a Holley 950 HP carb.

Before being run on the engine dyno, each of the heads had to be mocked up to determine not only the appropriate pushrod length, but also the correct head bolt/stud combination. Our 2.25-inch dyno headers presented a problem for the heads equipped with stock port locations and required use of head bolts in the lower holes to provide adequate clearance. A few of the heads required different middle stud lengths, but ARP helped cure the situation. All we had to do was juggle the necessary bolts and studs to properly secure the heads. Thanks also goes out to Fel Pro for supplying the necessary head and intake gaskets for our test.

The test Rat was finished using a set of hydraulic roller lifters, timing chain, and a couple of different sets of pushrods from Comp Cams. Comp also supplied the aluminum roller rockers (1.7 ratio) for our head shootout.

The finishing touches included a Milodon oiling system, an electric water pump, and balancer from Procomp Electronics. Prior to their time on the test mill, each head was given the once over on the flow bench, then set up to measure port and chamber volumes.

The heads supplied for the test shared the oval-port configuration, but that doesn't mean they were all the same. We started with a factory oval-port head to establish a baseline, in this case the peanut-port variety. We hoped to include a traditional oval-port head as well, but it fell through at the last minute.

The heads from Dart and Procomp Electronics were as-cast with no additional machining of any kind. Heads supplied by Brodix and Trick Flow Specialties both featured port matching, but the Brodix head carried it one step further with CNC work on the combustion chamber. The AFR, Edelbrock, and 049 heads from Dr. Js all combined full porting and chamber work.

As expected, the level of work applied to the heads resulted in differences in flow and power. Take note that the combustion chamber volumes varied from 110 cc to 121 cc, resulting in a difference in static compression of 1 full point. This alone was worth 3-4 percent in power, so bear this in mind when reviewing the results.

The one upgrade we would like to see on many of the heads is more valve spring pressure. At the top of the power curve, some suffered slightly due to inadequate spring pressure.

Power and price usually go hand in hand, but check out the retail prices to determine how your favorite does in the all-important bang-for-the-buck category. Next month, we'll be testing some popular rectangular port heads on a larger-displacement Rat.
Sucp 1206 005 Oval Port Big Block Chevy Cylinder Heads
ovalrecgask.jpg

Test 1: Chevy Peanut-Port Heads
peanutps.png

notice the huge difference in intake runner cross sectional area,between rectangle and peanut port heads
Our intention was to run a set of stock peanut-port heads and a set of stock oval-port heads, but our oval-port heads fell through. The stock peanut-port heads featured a 2.06/1.72 valve combination with 118cc combustion chambers. Closer inspection revealed that even our "stock" peanut-port heads had been milled sometime in their long life. The small valves, port volume, and flow numbers made them less than ideal with this healthy hydraulic roller cam, but they surprised us by exceeding 500 hp with peak numbers of 512 hp and 514 lb-ft of torque. Looking at the graphs, the peanut-port heads actually ran neck and neck with the aftermarket heads up to 4,500 rpm, which makes them ideal for intended low-speed truck applications. With a little porting, they make good heads for a mild street BBC, especially a small-displacement 396.

Notes: Out-of-the box 360 castings
Retail Price- N/A
Intake Valve Size-2.06
Exhaust Valve Size-1.72
Intake port vol-253 cc
Chamber Volume-117 cc [milled]
Peak Power-512 @ 5,800 rpm
Peak Torque-514 lb-ft @ 4,800 rpm
Avg HP [3,500-6,300]-453.4 hp
Avg TQ [3,000-6,500]-489.9 lb-ft
Tq @ 4,000 RPM-508.5 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 33 24
.100 57 51
.200 117 94
.300 185 128
.400 233 158
.500 247 179
.600 250 297
.700 250 211
heads2.jpg

pocketportpeanut.jpg
 
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Test 2: Airflow Research 265

The AFR 265 heads didnt produce the highest peak power and torque numbers of the test because of peak flow numbers. In fact, every aftermarket head we tested actually offered better flow number numbers at 0.700 lift (and many at 0.600 lift) than the AFRs. Even the ported 049 heads outflowed the AFRs at 0.700 lift, but our 0.580-lift cam never made it to 0.700 lift. Besides, power doesnt come from peak flow, it comes from maximizing flow in the usable lift range. Since the valve must open up to the maximum lift value, then close down, it spends twice as much time in the rest of the lift range as it does at the peak. Using the additional mid-lift flow offered by the AFR 265s, the 468 BBC produced 613 hp and 559 lb-ft of torque. The spring package provided by AFR allowed the hydraulic roller motor to rev cleanly to 6,500 rpm. In terms of average power production from 3,500 rpm to 6,300 rpm, the AFR 265s produced 501 hp and 536 lb-ft of torque, while knocking down 520 lb-ft at 4,000 rpm.
peanutvsafr265.jpg

Notes: Fully ported, chambers worked
Retail Price- $2,238
Intake Valve Size-2.19
Exhaust Valve Size-1.88
Intake port vol-266 cc
Chamber Volume-112 cc
Peak Power-612 hp @ 6,400 rpm
Peak Torque-559 lb-ft @ 5,300 rpm
Avg HP [3,500-6,500]-501 hp
Avg TQ [3,500-6,500]-536 lb-ft
Tq @ 4,000 RPM-520.3 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 37 30
.100 73 63
.200 164 141
.300 241 196
.400 298 239
.500 332 260
.600 331 273
.700 316 280
 
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Test 3: Brodix Race Rite Oval 270

The Brodix Race Rite oval-port heads featured 270cc intake ports that flowed just shy of 340 cfm--enough to support nearly 700 hp on the right application. Obviously, our mild combination could not take full advantage of what the Brodix heads had to offer, but they performed exceptionally well on the 468 nonetheless. Unlike the AFR or Edelbrock offerings, the Brodix Race Rite heads relied on CNC porting only in the combustion chamber. The intake ports received a minor gasket match, but the cutter was not allowed to do any serious work. The lack of CNC porting didnt seem to hurt the flow rates, as the intake and exhaust ports of the Brodix heads flowed 336 cfm and 270 cfm, respectively. This allowed the Brodix-headed 468 to produce 591 hp and 553 lb-ft of torque. The BBC averaged 492 hp and 528 lb-ft of torque while thumping out 512.8 lb-ft at 4,000 rpm.

Notes: CNC'd comb. chambers, intake ports
Retail Price- $2,796
Intake Valve Size-2.25
Exhaust Valve Size-1.88
Intake port vol-269 cc
Chamber Volume-111 cc
Peak Power-591 hp @ 6,100 rpm
Peak Torque-553 lb-ft @ 5,100 rpm
Avg HP [3,500-6,500]-492.7 hp
Avg TQ [3,500-6,500]-528 lb-ft
Tq @ 4,000 RPM-512.8 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 34 30
.100 69 64
.200 149 127
.300 220 163
.400 275 193
.500 315 225
.600 336 254
.700 333 270


ID suggest you select from heads from these sources
Jegs; 800/345-4545; Jegs.com

Summit Racing; 800/230-3030; SummitRacing.com

Scoggin-Dickey Parts Center; 800/456-0211; ScogginDickey.com


TRICKFLOW
http://www.trickflow.com/egnsearch.asp? ... 4294867081
http://www.trickflow.com/customerservice
1-330-630-1555 • 1-888-841-6556

BRODIX
http://www.brodix.com/heads/heads.html
479.394.1075

DART
http://www.dartheads.com/products/cylinder-heads
Dart Machinery; 248/362-1188; DartHeads.com


AIR FLOW RESEARCH
http://www.airflowresearch.com/
toll free: 877-892-8844
tel: 661-257-8124

Patriot Performance
Patriot Performance; 888/462-8276; Patriot-Performance.com


RHS
http://www.racingheadservice.com/rhs/cylinder-headshtml
Toll Free: 877-776-4323
Local: 901-259-1134

EDELBROCK
http://www.edelbrock.com/automotive_new ... main.shtml
Edelbrock; 310/781-2222; Edelbrock.com

BMP (world products)
http://www.theengineshop.com/products/cylinder-heads
Tel: 631-737-0372
Fax: 631-737-0467

BUTLER PERFORMANCE
http://www.butlerperformance.com/products/cylinder_heads/cylinder_head_labor.html
866-762-7527

BLUE PRINT ENGINES
http://www.blueprintengines.com/ind...sb-chevy-aluminum-cylinder-heads-cnc-machined
1800-483-4263

PRO-FILER
https://www.profilerperformance.com/
937‐846‐1333
 
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Test 4: Dart Pro 1 270 Oval-Port

The Pro 1 name from Dart has always meant power and this new 270 oval port cast was no exception. The Pro 1 was one of only two full as-cast heads to be tested. All others featured some sort of CNC porting, chamber work, or port matching. Obviously the designers were earning their money, as despite the virgin aluminum, the as-cast Dart Pro 1 offered impressive flow numbers. It's always easier to improve the flow with porting, but getting the results from a casting takes real talent. With enough airflow to easily support our test motor, the Dart-headed BBC produced 593 hp and 554 lb-ft of torque. The 111cc combustion chamber makes the Dart Pro 1 a perfect candidate for head swapping on a 7.4L truck motor. Yank a wrecking yard mule, stuff in a cam, and ditch the peanut ports in favor of a set of Dart oval ports and you have one serious street motor. The smaller chambers on the Dart head (compared to a typical 119cc chamber on peanut-ports) add both flow and compression to further increase power. The Dart Pro 1s showed the power of oval ports by averaging 494 hp and 529 lb-ft of torque and offering 509 lb-ft of torque at 4,000 rpm.

Notes: Totally unported, as-cast
Retail Price- $2,995
Intake Valve Size-2.25
Exhaust Valve Size-1.88
Intake port vol-274 cc
Chamber Volume-111 cc
Peak Power-593 hp @ 6,100 rpm
Peak Torque-554 lb-ft @ 5,300 rpm
Avg HP [3,500-6,500]-494.0 hp
Avg TQ [3,500-6,500]-529.0 lb-ft
Tq @ 4,000 RPM-509.8 lb-ft

Flow Data: CFM @ 28-ins
Lift In EX
.050 36 34
.100 71 69
.200 158 117
.300 235 159
.400 290 204
.500 323 234
.600 324 252
.700 325 267
 
Test 5: Dr. J's Ported 049 Oval

Popularity, availability, and cost all make a factory oval-port head appealing. Because so many enthusiasts not only have heads, but decided to massage them, we opted to include a set of ported 049s in this test. The factory 049 heads came from Dr. J's and were treated to their typical valve upgrade, full porting, and even a slight milling to get the chamber volume down to 118 cc. It is all but impossible to get the chamber size down to the 110cc range offered by the aftermarket heads, but the flow numbers were certainly right in the ballpark. The drop in compression caused by the larger chamber volume hurt power slightly through the entire rev range, but the ported 049s demonstrated why so many BBC owners insist on porting the stock stuff.

Equipped with the Dr. J heads, the 468 produced 576 hp and 538 lb-ft of torque. Torque production exceeded 515 lb-ft from 4,500 rpm to 5,800 rpm, while the BBC averaged 481 hp and 515.8 lb-ft of torque. Down at 4,000 rpm, the iron-headed big-block produced 504.7 lb-ft of torque. The one problem with iron heads is obviously the weight.

Notes: Reworked factory heads
Retail Price- $1,599 (porting customer-supplied castings)
Intake Valve Size-2.25
Exhaust Valve Size-1.88
Intake port vol-267 cc
Chamber Volume-118 cc
Peak Power-576 hp @ 6,000 rpm
Peak Torque-538 lb-ft @ 5,100 rpm
Avg HP [3,500-6,500]-481.4 hp
Avg TQ [3,500-6,500]-515.8 lb-ft
Tq @ 4,000 RPM-504.7 lb-ft

Lift In EX
.050 33 34
.100 73 71
.200 152 120
.300 228 162
.400 282 188
.500 320 215
.600 336 238
.700 329 246
 
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