I use the following types of heads
Look over the flow numbers very carefully.
Compare the flow at the lift matching your camshaft.
Some heads flow more at .500" compared to another head, but may flow less at .600"
DO NOT choose a head with larger ports than you need.
Horsepower is a function of RPM.
As such big horsepower numbers require high port flow.
If you are building torque for a street performance vehicle using overly large ports will result in reduced torque, poor acceleration.
This is because airflow through the port will be slower than desired.
The engine will come alive above 3500rpm, but if you are not revving it pass 6000 you will not realize the full potential of the ports.
Using a larger port works best with long duration and high lift camshaft and the use of a high speed torque converter.
Typically 180cc is considered as large as you would want for the average high performance street engine below 390cid.
A 400 to 420cid may work well with 200cc.
However aluminums heads such as the Air Flow Research street performance, Canfield and TrickFlow Twist Wedge heads all work very well with 195cc ports.
This is consider the result of more effective port design.
You will notice a larger port does not necessarily flow more.
While I do not attempt to favor one head manufacture of another,
AFR heads are consider by many to best the best performing overall.
They cost just a little more and until they get the new production shop up and running at full capacity, a set of Chevrolet heads must be order anywhere from 6 to 10 weeks in advance.
Flowing is a long list of heads you can compare. Look very carefully at the numbers and comments.
I will be more than glad to help you choice a pair of heads for your engine.
When trying to choose between an iron or aluminum head, consider the fact that aluminum dissipates head more quickly than iron. Retaining heat in the combustion chamber produces more power.
As a result the compress ratio needs to be high in an aluminum head to produce the same power output as an iron heads.
However, an aluminum head will allow you to raise the compression more than just the compensation requirement before pre-ignition or detonation (pinging) becomes a problem.
The result is additional horsepower and torque.
Maximum compression rations will vary due to attitude, octane rating of premium gasoline where you live, the camshaft duration and final drive ratio.
Building a motor with too high of a compression ratio will result in pinging which prevents further power increase and will over time pound out rod bearings and break ring lands. In extreme situation you may pound a hole through the top of the piston.
Running a compression ration .2 to .4 below the maximum recommended compression ratio for your application will only cost you 5 to 10 horsepower, but buy to a much longer running engine.
In studying head flow numbers keep in mind that they are only a guide. High flow numbers don't always equal more horsepower, and more horsepower doesn't always equal faster acceleration. It can be frustrating to choose the best head and the best camshaft for an application. So many choose, and all manufacturers cliam their product is the best. Dyno or track testing is the only real way to know for sure, but who can afford to do all that testing. I look to my experience the experiences of other engine builders, and magazine test articles to help, but that's all they are a help, until the engine is run, we all have to wait and see.
One last note. If you must pass a smog check your choices will be limited.
Some Edelbrock and TrickFlow heads are 50 State legal, carrying a CARB number.
Over the last few years coatings have become increasing popular. this is due to the fact that a coating can reflect heat back into the expanding gases during the power stroke.
This not only produces more power but will allow a higher compression ratio before detonation occurs.
Coating a piston cost about $20 to $25 each, but for the full effect to be realize you should also coat the combustion chamber and valves.
As a result of these added cost, this process is considered a premium for engine builds with a higher budget.
I can supply Mahle pistons for some applications (350s and 383s and some Ford engines) for about $550.
These pistons are very strong forging, come fully coated, are some of the lightest weight pistons available and have come unique narrow rings for less drag and more horsepower included in the purchase.
Ask for details.
The following is a reprint fro Chevy High Performance Magazine.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.