sources for cylinder head flow numbers

[grumpyvette]

http://www.purplesagetradingpost.com/su ... eads1.html

http://racingdownloads.com/racing_software-26.html

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

http://www.superchevy.com/how-to/83138- ... ock-heads/

http://www.strokerengine.com/SBCHeadsFlow.html

http://www.hotrod.com/articles/ccrp-1209-eight-budget-sbc-head-shootout/

http://www.hughesengines.com/TechArticl ... risons.php

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

http://www.carcraft.com/techarticles/11 ... index.html

http://www.summitracing.com/parts/tfs-3 ... /overview/

http://www.summitracing.com/parts/tfs-3 ... structions

you are aware theres reasonably priced aluminum heads designed for a small bore sbc that out flow standard vortec heads, so don,t think those are automatically your best option.

look this is not a guessing game (selecting the correct port size, there are known guidelines )you select and verify the correct port size and cross sectional area, using know calculations, valve diam. and flow rate for the application, verify clearances in the valve train, intake runner length and cross sectional area and that the cam lift duration and LSA, and make sure the valve train components are compatible for the intended rpm band and stress levels,
you match the cams intended rpm and power band to the displacement and compression ratio, exhaust scavenging ,make sure the valve curtain area exceeds the port cross section slightly , select the cam lift and duration to maximize the port flow,potential, select headers designed to operate in the same power band, select a drive train that keeps the engine in that power band most of the time.
if you read thru the posted info I will agree that a great many cylinder heads get selected on the basis of posted flow numbers or price alone, and the fact is that the cam timing, intake design,operational rpm band, displacement ,compression ratio and exhaust scavenging all have a pronounced effect on how well the fuel and air flow thru a cylinder head port, and you don,t always get the best horse power by selecting the head with the highest posted and advertized flow numbers.
I'd also point out that the exhaust gases are physically forced out by the piston on the exhaust stroke and given a huge help in exiting the cylinder if you have a properly designed header that scavenges the cylinder,and that rapidly exiting exhaust gas does help to draw in the next intake charge PROVIDED the cam timing and exhaust header are properly matched, and since flow benches measure flow at a static valve lift and engine have a piston rotating at maybe 6000rpm and valve that opens and closes 55 times PER SECOND and theres no exhaust scavenging ,while the heads tested,theres no way in hell that a flow bench accurately duplicates flow conditions in a running engine

http://www.rbracing-rsr.com/runnertorquecalc.html

upgrading SBC crate engine heads

Will L 98 ,58cc, 160-165,cc port alum heads (14101128)help performance on a 290hp small block thank you pete. you may find info in links you can use else-ware in many threads https://garage.grumpysperformance.com/index.php?threads/bbc-related-links-and-useful-info.17140/ as compared to...

garage.grumpysperformance.com

sellecting cylinder heads

READ THIS THREAD AND LINKs and SUB LINKS AS ITS IMPORTANT TO UNDERSTANDING SOME FACTORS, and theres a ton of useful info in the links read these threads and sub-links also, as they contain good info, if you fail to read thru the sub links youll miss a ton of useful info, don,t think published...

garage.grumpysperformance.com

Stock out of box 461x heads 1.940/1.500
but with very light 3-angle valve job
tested on SF-600 FlowBench
Flow tested at 28" on 4.000 Bore fixture

Lift----Intake----Exhaust
.200---- 99.6-----88.0
.300----155.2-----124.3
.400----189.0-----141.9
.450----190.6----------
.500----190.6-----142.2
.550----192.0----------
.600----192.6-----146.4
*** Short exhaust pipe on exhaust ports


Maxed out porting job, unwelded, 461 X SBC
no epoxy , with 2.055/1.600 valves
tested on SF-600 FlowBench
Flow tested at 28" on 4.000 Bore Fixture

Lift----Intake----Exhaust
.200----131.1-----116.1
.300----187.7-----152.7
.400----230.0-----193.9
.450----243.3----------
.500----259.7-----212.5
.550----266.5----------
.600----273.2-----245.1
.650----278.0----------
.700----282.0-----253.3
.750----283.6----------
***Short exhaust pipe on exhaust ports

Basically this was the sort of Flow
we were getting for C/ED dragster 316 cid
a very long time ago
Note: if ditch near spark plug, between
area around both valves to plug
is welded up ,...then another 4 to 8 cfm
is gained on Intake flow (461 X SBC)
if you also wanted to start welding the entire
chamber floor lowering CCs and increasing
short turn radius on 461x ,
and welding up intake port's roof
water jacket solid .... then it was
worth another 4 to 8 cfm gains .
so some of the very best WELDED up
461x heads were approx 299 cfm @ 28 inches

==========================================
Stock out of box 034 Cast-Iron Bowtie heads
with factory valve job and 2.020/1.600
Tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----117.9----107.9
.300----169.5----123.8
.400----205.0----146.2
.500----216.6----146.6
.550----228.3---------
.600----222.1----148.8
.650----215.8---------
.700----216.8----148.8
.750----217.8---------
***with pipe on exhaust ports


Cast-Iron Chevy Bowtie heads #034 castings
with 2.085/1.580 valves
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----127.7-----104.6
.300----189.2-----158.8
.400----238.5-----204.0
.450----256.6----------
.500----271.0-----216.0
.550----281.5----------
.600----288.6-----218.6
.650----293.3----------
.700----298.4-----221.1
.750----304.3
.800----308.3
.850----311.4
***with pipe on exhaust ports
all out porting but no epoxy or welding


Brodix Track 1 SBC with Manley 2.080/1.600
Best CNC porting ..by Weld Tech
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----125.5-----120.4
.300----189.8-----153.7
.400----245.8-----190.1
.450----269.7----------
.500----286.7-----228.3
.550----295.1----------
.600----294.7-----244.7
.650----301.4----------
.700----301.4-----252.0
.750----300.3----------
***with pipe on exhaust ports

-----------------------------------------
Cast-Iron Chevy Vortec heads #10239906
1.940/1.500 OEM valve job and shape
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----121.4-----98.2
.300----179.4-----123.8
.400----219.2-----137.5
.450----230.6----------
.500----220.8-----146.0
.550----221.6----------
.600----223.1-----151.9
.650----224.7----------
*** No-Pipe attached , bare exhaust ports


--------------------------------------------
Cast-Iron Chevy Vortec heads #10239906
Manley 2.055/1.600 valves
2nd Level porting , not yet all out
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----143.9-----119.5
.300----192.2-----169.9
.400----235.7-----195.5
.450----252.3----------
.500----264.1-----207.0
.550----258.6----------
.600----265.1-----212.6
.650----271.0----------
.700----271.1-----215.6
.750----272.0----------
***No-Pipe attached , bare exhaust ports


-------------------------------------------
Chevy Fast Burn heads with Manley 2.125/1.600
1st Level full porting job, not yet all out
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----134.4
.300----190.0
.400----235.5
.450----254.3
.500----270.4
.550----277.9
.600----270.0
.650----275.0
.700----277.5
.750----279.5
.800----279.5
****No flow numbers available on exhaust
were lost on computer's harddrive !!!
-----------------------------------------


GM Chevy LT-1 aluminum heads 2.055/1.600
1st Level porting
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----138.4----115.3
.300----193.2----154.5
.400----235.7----182.5
.450----250.3---------
.500----261.2----193.2
.550----259.2---------
.600----260.2----200.6
.650----262.2---------
.700----262.2----205.7
.750----263.1---------
.800----264.1---------
***No-Pipe attached , bare exhaust ports
.600" Lift with Pipe flowed = 223.6 cfm

-------------------------------------------
Dart Pro 1 Aluminum 215 CC ports
out of box shape as shipped by Dart
2.055 valve on 2.020 seat lapline
1.600 valve on exhaust
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----128.5----115.3
.300----181.3----148.5
.400----226.3----178.4
.450----243.4---------
.500----257.0----192.1
.550----268.1---------
.600----271.2----198.5
.650----262.2---------
.700----266.1----201.1
.750----266.1---------
.800----261.2----203.2
.850----257.2---------
***No-Pipe attached, bare exhaust ports

------------------------------------------
Dart Pro 1 Aluminum 215 CC ports
2nd Level porting
2.125/1.600 valve combo
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----147.8----111.4
.300----208.0----167.3
.400----251.5----198.9
.450----269.4---------
.500----284.6----214.3
.550----295.3---------
.600----299.6----220.3
.650----304.3---------
.700----308.3----224.1
.750----309.5---------
.800----309.5----227.3
.850----310.3---------
.900----309.9---------
***No-Pipe attached, bare exhaust ports

--------------------------------------------

Dart Pro 1 Aluminum 230 CC ports
out of box shape as shipped by Dart
2.055 / 1.600 Manley valves combo
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----123.0-----117.4
.300----179.4-----147.7
.400----223.1-----175.0
.450----241.7----------
.500----257.0-----193.2
.550----269.6----------
.600----278.7-----193.2
.650----270.4----------
.700----267.3-----204.9
.750----268.1----------
.800----265.7-----208.1
***No-Pipe attached, bare exhaust ports
-----------------------------------------

#492 SBC cast-iron castings (Old LT-1 heads)
Stock out of box factory shape
with 2.020/1.600 valves
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----115.2-----105.4
.300----165.2-----132.5
.400----195.6-----138.5
.450----202.3----------
.500----208.9-----143.0
.550----208.1----------
.600----207.3-----146.6
.650----208.7----------
.700----210.1-----146.6
***with pipe on exhaust ports

---------------------------------------------
World Products - Dart SBC Cast-Iron heads
stock out of box shape and valve job
( as produced for sale in Aug 1988 )
these were some old flow test numbers
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----127.5-----107.9
.300----180.7-----136.8
.400----208.9-----145.8
.450----219.4----------
.500----220.4-----150.5
.550----226.8----------
.600----233.3-----154.4
.650----236.7----------
.700----238.3-----155.7
***with pipe on exhaust ports
--------------------------------------------
TrickFlow aluminum SBC heads with 2.020/1.600
out of box shape and valve job, as shipped
Flow tested on SF-600 FlowBench
Flow tested at 28" on 4.000" Bore Fixture

Lift----Intake----Exhaust
.200----139.9-----100.3
.300----200.1-----133.2
.400----234.6-----155.8
.450----238.5----------
.500----237.7-----174.2
.550----238.1----------
.600----237.5-----183.5
.650----236.9----------
.700----238.9-----189.9
***No-Pipe attached, bare exhaust ports
at .700" Lift Exhaust flows =208.7 CFM @ 28
with short pipe attached to heads

 

[grumpyvette]

http://www.airflowresearch.com/super-chevy-apr-2010-210cc-sbc.php

profiler new port 210cc SBC heads. 2.055 master valve (it has a 30º backcut) and flowed the head on a 4.125 fixture. Exactly a 90% throat.

http://www.profilerperformance.com/sbc-heads-176.html


.200/158.7
.300/211.0
.400/261.5
.500/285.0
.600/289.9
.700/294.7
.800/294.8

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

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Intake Port cc & CFM @. 500" Lift

Chevrolet Production 441 Iron Head 155/201

The 882 head may have out-flowed this head but with the addition of larger 2.02-inch intake valves and some decent pocket port work these heads will out flow the 882’s. Keep in mind that with a small 155cc port volume these heads are great for making torque.

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Chevrolet Production Iron 882 Head 151/205

This head had the smallest port size of all the heads we tested. A set of 2.02/1.60-inch valves can be swapped in but be aware that without blending in the short side radius, the results usually find lost airflow.

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Chevrolet Production 462 Iron Head 156/212

This head was a small chamber head used on 327ci motors until the end of 1968. The flow can be improved a little with larger valves and port work but the additional cost of this is impractical in comparison to what you can by some other aftermarket casting for.

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Chevrolet Production Vortec Iron Head 885 170/239

This head can be seen as a sleeper when compared to other GM production heads. It outflows the LT-1 aluminum Corvette head on the intake side, plus its mid lift numbers are very impressive. This head is perfect when iron heads are required. GM designed this head and put it on trucks as well as on the later Impala SS but with a different intake bolt pattern. As for production pieces these are one of our favorites.

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Chevrolet Production L98 TPI Aluminum Head 163/196

This aluminum head was used on the Corvette TPI engines from the mid-Eighties until the LT-1 1992 motors were introduced. The 882-iron head out-flowed this head across the board. This piece is not our first choice for a performance head considering that the largest valve this head fits is a 2.00/1.55-inch combination and it has a 58cc chamber.

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Chevrolet Production GM LT1 372 Aluminum Head 170/214

The LT-1 head was the next generation head developed for the small blocks after the L98 head. This head uses a reverse-cooling system, which means it can not be swapped onto older blocks. The 0.400-inch airflow numbers are great and with some port work, the addition of 2.00/1.55-inch valves can really wake these heads up.

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Chevrolet Production LT4 Aluminum Head 195/250

The LT-4 is substantially different from the LT-1 casting, and the flow numbers explain why. The larger intake ports are definitely a contributing factor. For a production head these babies put up some pretty good flow numbers. Remember, like the LT-1 the LT-4 can only be used on a reverse cooling system block.
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Chevrolet LS1 Aluminum Head 204/240

GM won’t be left out of category 3 with these heads. This head has great 0.400-inch lift numbers as well as a good E/I ratio. They also feature a more flat valve angle (15 degrees) in order to promote a better combustion chamber that’s shaped like a kidney to help direct combustion and reduce possible detonation. Remember that this head will not interchange with pre-‘93 small-block heads.



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AirFlow Research 180 Aluminum Head 181/250

This head is the smallest of AFR’s line. It is intended for engines up to 350ci. The flow numbers are especially impressive on the exhaust side of this head, leading us to believe that a single pattern cam may be the best choice here. The E/I relationship is outstanding with and 84%, almost higher than any other head in this category.

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AirFlow Research 190 Aluminum Head 191/262

This head has the best flow numbers of all the category 2 heads. Offering great flow throughout the entire lift range you can see this head doesn’t just put up one big number at maximum lift. If you’re looking for great flow from a mid-sized cylinder head this is definitely one of the top contenders.

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AirFlow Research 210 Aluminum Head 215/271

Here is an extraordinary head. It has larger intake ports but with 240cfm at 0.400-inches of lift who cares? The E/I ratio is an incredible 75% making it hard to find anything wrong with these heads. This head may be a little much for a mouse motor but it is perfect for a big mouse somewhere in the 383 inch range up.
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Brodix-8 Pro Aluminum 181/254

This head features larger 2.08/1.60-inch valves combined with a 181cc-intake port. With smaller intake port this head flows outstanding at 220cfm by 0.400-inches of lift and even better by 0.500-inches. Combined with a mid-sized port this, this is an outstanding choice for a strong 350ci or 383ci motor.

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Brodix Track 1 Aluminum Head 216/246

The Track 1 head may be down on the numbers at 0.400-inch lift but it’s really competitive once it sees the 0.500-inch lift point. Add some short-side radius work and wow you’ve got a killer head. If you have a set of these heads there’s definite potential.

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Brodix -11X 220 Aluminum Head 216/246

Brodix offers this large-port, 23-degree valve angle, small-block head as one of its largest ports in the stock valve-angle lineup. The low lift numbers are down a bit but in comparison to some of the others once the lift numbers increase you can see there is some serious airflow. These come available with minor or major port work depending on how you order them.

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Brodix -1X Aluminum Head 223/278

The Brodix -1x heads feature a 40/60 valve spacing, meaning the centerline of each valve has been moved away from its standard location to accommodate a larger diameter valve and move both valves away from chamber walls for unshrouding. This means special offset shaft mounted rockers are needed and available from Brodix. It seems like a lot of R & D went into these bad boys and the numbers show it.

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Canfield Aluminum Head 195/258

Canfield only sells this head with valves. One area to pay close attention to is the excellent low and mid-lift numbers. This head actually out-flows the Category 3 heads from 0.050- through 0.400-inches of lift.

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Canfield 220 Aluminum Head 223/260

This race oriented small-block head requires the use of 0.150-inch offset intake rocker arm to accommodate the repositioned intake valve. The idea of spreading the valves apart is to increase valve diameter and improve flow. This head has 2.08/1.60-inch valves and probably works best on larger displacement mouse motors around 383-plus cubic inches.

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Dart Iron Eagle S/S 165/210

Dart offers everything from street performance heads to full race heads. This Iron Eagle piece is the smallest head at 165cc port volume but its just what you need when building a stout street motor that sees occasional strip time. Compare its flow numbers to others and you can be the judge on this one.

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Dart Iron Eagle 180 174/210

This head is also a big brother but to the 165cc Dart Iron Eagle head. The 180cc head reveals a respectable intake flow curve and an outstanding exhaust port. This head comes in many different combinations. You can order the head with straight or angle plugs, a 64cc or 72cc chamber, and in iron or aluminum. You will notice this head has better mid lift intake flow figures but the same full lift numbers as the 165cc heads, however the exhaust side flows better.

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Dart Iron Eagle 220 220/258

The Dart Iron Eagle head here offers a budget alternative to the aluminum Conquest head. With similar flow numbers the only real big difference here is iron verse aluminum and cost. This head is offered in 200 or 220cc intake ports and with 2.02 or 2.05-inch intake valves.

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Dart Conquest Iron 220 220/252

This head really likes to flow at lifts above 0.500-inches. The E/I ratio at 0.400-inch is a very good 72% and 68% at 0.500-inches. This head comes machined for both center-bolt and perimeter-style valve covers. The Conquest can be optioned with 200 or 220cc intake ports, valves up to 2.08/1.60, and in 64 or 72cc chamber sizes.

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Dart Pro 1 Aluminum 215 221/253

This is perhaps one of the most versatile heads out there. While the low lift numbers don’t stand out, the higher lift numbers are on par with the rest of the heads on the market. This head is definitely best on high winding motors where consistent rpm is what wins a race.

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Dart Iron Eagle 230 229/254

This is the largest of the Dart Iron Eagle series heads. They perform best on motors above 400ci-inches and with cam lifts above 0.500-inches lift. The E/I ratio is acceptable and the castings are made of good quality. These heads flow well and do not really require too much handwork to improve airflow.

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Edelbrock Performer Aluminum 166/235

This head may first appear subtle in comparison to its flow numbers but don’t be fooled. The 166cc port makes for great torque and the E/I flow relationship is good. This head is perfect for a street/strip application. In our own personal experience we had a 355ci motor with 9:1 compression, a streetable Comp Cam (DEH 275), and an Edelbrock RPM manifold. With this combination we were able to achieve 420hp at 6,000rpm and 440 lb-ft of torque at 4,250 rpm.

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Edelbrock Performer RPM Aluminum 170/237

The Edelbrock RPM head is the big brother to the Performer version. It still retains a small 170cc intake port volume providing great torque down low where it’s needed. The E/I percentage is no less than 70% with much higher numbers in the low-lift areas. This head is a step up from the Performer, flowing more air, which in return will make more power on the top end.

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Edelbrock E-TEC 170 Vortec Aluminum 170/240

With the tremendous popularity of GM’s Vortec head, Edelbrock decided to design a head around the GM casting. This head features a 1.94/1.55-inch valve combination, and different port configuration allowing it to out perform the stock production Vortec head. However, the E-TEC heads are aluminum typically costing more than the production GM heads.

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Edelbrock E-TEC Vortec 200/252

This head is the next step up from the smaller 170 E-TEC. It features larger valves and bigger intake ports. However, a Vortec style intake manifold must be matched with these heads. Up to 0.500-inches these heads don’t really out flow the stock Vortecs. On the other hand their exhaust ports are extremely efficient which help improve performance throughout the entire power curve. They are also aluminum, which can allow more compression with out detonation.

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Edelbrock Victor Jr. Aluminum 219/255

This is an impressive head. It features a kidney shaped combustion chamber keeping the combustion moving, the flow is awesome from 0.400-inches all the way up to our tested 0.700-inches, and the E/I ratio is an amazing 81%. We see a head that flows some serious air and likes high lift roller cams.

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Holley 300-570 Aluminum 172/232

This head from Holley comes with angled plugs and 69cc chambers, which are a big change from the stock 76cc smog chambers. The combustion chamber is typical of a late model design with a kidney shape that increases combustion turbulence lessening the possibility of detonation.

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Holley SysteMAX Aluminum 186/242

This head is very similar to the -8 Brodix but it appears to flow a little better on the exhaust side. Again this head looks like it offers great torque potential with its well-proportioned 186cc-intake runner

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Pro Action Iron 220 225/239

These heads can be purchased in many different intake port sizes. They are available with 180, 200, 220, and 235cc intake ports. They also feature a 64cc and 72cc chamber for your desired compression levels.

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Pro Action Iron 235 Iron 245/242

These are the largest of the Pro Action lineup. The heads are advertised as 235cc intake ports but in our testing we found them to be 245cc’s. These heads are definitely for use on big mouse motors that like to see some rpm.

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Trick Flow Specialties 195 195/250

These heads may not flow the biggest numbers but there should be little question regarding their performance that they can perform well. In CHP’s Nov. ’99 issue they were bolted on a mild 383ci motor and were able to pump up peak engine power by 15.5%. These heads offer some of the best power for the dollar on a mild small Chevy.

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TFS Twisted Wedge 200/254

In an attempt to be different for the better, this TSF twisted Wedge head changed the valve angles from 23 degrees to 13 degrees. The really big difference here is what the exhaust side of this head is capable of. Only one other head (AFR 210) was even close on the exhaust side. The E/I was also a very respectable 77%. This head really can wake up your engine.

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World Products Iron S/R Torquer 170/225

This head is very similar to the 882 head tested earlier. The valves are larger and the flow numbers at 0.400-inch lift are almost identical. At 0.500-inch lift the flow is up 15% over the 882 head. With prices to rebuild stock heads increasing all the time these heads would probably be one of your better investments.

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IF YOU HAVE A SET OF REALLY DEEP POCKETS
http://www.speierracingheads.com/SRH2.50.htm

heres some BBC head info

 

[grumpyvette]

http://www.thirdgen.org/techboard/tbi/3 ... dflow.html

it should be very obvious that most factory heads are very flow restrictive,
and are built to be functional durable and cost effective to make in vast quantity,
not particularly made to boost power or torque.
as a basic guide your ideal street/strip
performance small block chevy head
IDEALLY ALUMINUM and USES LARGER VALVES

should flow at least 250 cfm at .500 lift and ideally 280 cfm plus at .700 lift

210cc All American Aluminum 23° SBC Racing Heads, Assembled, Straight​

Producer and Seller of aluminum aftermarket cylinder heads, intake manifolds and engine accessories. Specializing in big block chevy ,small block chevy, big block ford and small block ford.

www.profilerperformance.com

as a basic guide your ideal street/strip performance BIG block chevy head
should flow at least 350 cfm at .500 lift and ideally 380 cfm plus at .700 lift

example

AFR 357cc BBC Rectangle Port Cylinder Heads 100% CNC Ported No Parts - Air Flow Research 3570 - TREperformance.com​

TREperformance sells new AFR 357cc BBC Rectangle Port Magnum aluminum cylinder heads from Air Flow Research for almost any Chevy big block vehicle, this is part # 3570.
treperformance.com


These are the flow results before any port work:
Also posted here: http://www.thirdgen.org/techbb2/show...hreadid=177593 (L98 cast iron heads...at machine shop)

14101083 heads 1.94 intake / 1.50 exhaust
numbers @ 28" of mercury for comparison

Intake
Lift_______CFM__Potential (based on 1.94 valve area)
0.097..........52.................66
0.194..........101...............131
0.291..........145...............196
0.388..........167...............226
0.485..........179...............242
0.582..........185...............253

Exhaust
Lift_______CFM___Potential (based on 1.50 valve area)
0.075..........35.................38
0.150..........62.................78
0.225..........87.................114
0.300..........105...............152
0.375..........106...............165
0.450..........106...............171

The flowbench operates at 10"...I multiply the flow results by 1.67 to get 28" for comparison. The inlet was radiused...and there was a pipe on the exhaust. So...these heads were just that bad, I guess. The heads were stock valve, with apparently some crappy valve job work done on them before. No port work had been done.

Using only carbide cutters, I opened up the intake opening, opened up the pushrod pinch, removed as much casting as I could get to, and pocket ported and bowl blended the best that I could do. Same for the exhaust except I did not touch the exit area, just removed casting, pocket ported some, and tried to blend it and remove the sharp edge on the short side. This was the 1st time I have ever truely looked at a set of heads, much less ported any.

Having said that, here are the results on the same flow bench at the same lifts with the stock valves, and then some stock type Stainless Steel Replacement valves:

Stock Valves
Intake
Lift_______CFM__Potential (based on 1.94 valve area)
0.097..........49.................66
0.194..........100...............131
0.291..........146...............196
0.388..........183...............226
0.485..........200...............242
0.582..........200...............253

Exhaust
Lift_______CFM___Potential (based on 1.50 valve area)
0.075..........35.................38
0.150..........61.................78
0.225..........91.................114
0.300..........125...............152
0.375..........138...............165
0.450..........139...............171

Stainless Steel Stock Type Valves...brand unknown
Intake
Lift_______CFM__Potential (based on 1.94 valve area)
0.097..........54.................66
0.194..........108...............131
0.291..........158...............196
0.388..........189...............226
0.485..........206...............242
0.582..........203...............253

Exhaust
Lift_______CFM___Potential (based on 1.50 valve area)
0.075..........30.................38
0.150..........63.................78
0.225..........102...............114
0.300..........137...............152
0.375..........144...............165
0.450..........144...............171


Side by side comparison
Intake
Lift_______CFM
0.097...52......49....54
0.194...101....100...108
0.291...145....146...158
0.388...167....183...189
0.485...179....200...206
0.582...185....200...203

Exhaust
Lift_______CFM
0.075....35.....35...30
0.150....62.....61...63
0.225....87.....91...102
0.300....105...125...137
0.375....106...138...144
0.450....106...139...144


I think I have done well so far. Heads are cut for 2.02/1.6 valves now. Just need valve job, blend again, polish exhaust, and 80 grit the intake side, and I will be done. I have the Manley RaceFLo Valves to top it off. I will flow test again when I'm finished.

Cutting for the valves cost me $125.

let me know what you think. At least I didn't butcher them. I have seen where others lose flow at the bottom, and gain at the top. I didn't seem to lose much, if any, at the bottom, and gained some on the top. I hope the blending, bigger valves, valve job, and Manley valves will help considerably.

Here are some other stock flow numbers from other posts for comparison sake:
Corvette Aluminum # 113
Lift/Intake/Exhaust
.100 62 49
.200 116 98
.300 161 130
.400 185 152
.500 195 159

350 Cast Iron # 083
Lift/Intake/Exhaust
.100 44 41
.200 101 82
.300 155 125
.400 182 137
.500 196 140
__________________

Here are the flow numbers for my 416 heads.
Both intake and exhaust have been ported. Intake runner cced in at 178.6cc and exhaust 65cc The heads were flowed with a stock 1.84 intake valve and a Manley 1.5 exhaust valve. The intake had a radiused entry in place and the exhaust was straight out of the port. The flow bench was fitted with a 3.8" bore diameter adaptor only because it was the closest size avaliable.

Lift Intake Exhaust both @ 28"
.05 29.4 24.6
.10 57.4 48.3
.15 88.3 75.0
.20 122.1 100.2
.25 152.2 113.9
.30 172.9 128.7
.35 188.7 139.4
.40 201.8 147.3
.45 213.3 152.2
.50 217.8 159.2
.55 220.7 161.2
casting number 14022601 heads. Removed casting flash, gasket matched heads, intake, & exhaust manifolds.
Here are the flow numbers @ 28 in/H20.


Lift Intake Exhaust
.050 35.60 15.00
.100 72.40 47.00
.150 105.8 72.50
.200 133.4 98.00
.250 154.1 117.5
.300 180.6 137.0
.350 195.5 145.0
.400 209.3 153.0
.450 217.4 155.0
.500 224.3 157.0