Thread: How to choose the correct Heads

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I have a 355 chevy with small dome pistons in it. I recently had a set of holley alluminum heads on it and the best I got out of the engine was a 12.58 in the 1/4. Everyone that I have spoken to about the engine said that the heads were to small. So I sold them Nobody can seem to give me a strait answer on what heads to go with. If anyone has any suggestions please let me know. Thank you

Originally posted by shawn74
I have a 355 chevy with small dome pistons in it. I recently had a set of holley alluminum heads on it and the best I got out of the engine was a 12.58 in the 1/4. Everyone that I have spoken to about the engine said that the heads were to small. So I sold them Nobody can seem to give me a strait answer on what heads to go with. If anyone has any suggestions please let me know. Thank you

WHAT WAS THE PORT VOLUME ON THE HEADS? WHAT WHERE THE FLOW NUMBERS? HOW MANY R.P.M.S. DID YOU TURN THE ENGINE? WHAT WHERE THE LIFT VALUES ON THE CAMSHAFT?

I've seen some magazine buildups and dyno tests with the Holley heads and frankly, they weren't that impressive. Get us the data that Erik asked you for so we can give you an intelligent answer.

Chambers are easy to size. Runners take a little trial and error. If you want to run 12's and under, 200-220 cc runners will probably be ideal. Give Air Flow Research a call, they make some of the best heads and will point you in the right direction. For the chambers, smaller is better, but so are flat top pistons. You want to run the smallest combustion chamber you can along with a flat top piston while still meeting your target compression ratio and having enough room around the valves to get good airflow.

Originally posted by shawn74
I have a 355 chevy with small dome pistons in it. I recently had a set of holley alluminum heads on it and the best I got out of the engine was a 12.58 in the 1/4. Everyone that I have spoken to about the engine said that the heads were to small. So I sold them Nobody can seem to give me a strait answer on what heads to go with. If anyone has any suggestions please let me know. Thank you

how heavy is the car or truck? how big is the cam ? what is the cfms of the carb? how much cr ? how big are the headers what gear in the rear end. what is the stall on the converter what is the 60 feet do you have a good fuel pump .how do you know the heads are bad?? there is way to many things. could be the heads?? or it may be many things or it may be you need more engine to move what you have. was it tune in good .did you try deferent cam. intake. carb.how much do you want like HP or 1/4times ??

Originally posted by 76GMC1500
Chambers are easy to size. Runners take a little trial and error. If you want to run 12's and under, 200-220 cc runners will probably be ideal. Give Air Flow Research a call, they make some of the best heads and will point you in the right direction. For the chambers, smaller is better, but so are flat top pistons. You want to run the smallest combustion chamber you can along with a flat top piston while still meeting your target compression ratio and having enough room around the valves to get good airflow.

YOU STATE SMALLER CHAMBERS ARE BETTER.NOT ALWAYS.SOMTIMES IF THEY ARE TO SMALL THE ACTUALLY (SHROUD) THE VALVES.

The heads that I had were 184cc intake runners and if I remember correctly the chamber size was 72cc. The car is a 74 nova weighs 3190 with 410 spool in the rear end. I was shifting the car at 6500 rpms. The converter is a 3000 stall The carb is a 750 holley vac seconary. No I don't know that the heads were the problem. Have a good carter elctric fuel pump. Not real sure on what size the headers are. The 60 foot times were 1.7

what was the lift on the cam,and cr and how tall on the rear tires. i do not think the heads were bad. but what times did you want to see?? the amount you have told me i think it will run some were in the low 12s with what your have. your 60 foot be a bit better it may like more gear and 3500 on the stall.

the lift on the cam was 507intake 532 exhaust duration is @.50 242 intake and 250 exhaust. The rear slicks were 28x9 15 I was lookin to get somewhere between mid 11's real low 12's

try some more gear rear like a 430 or 456 and if this cam is a solid cam you may need to go bigger. but how much cr do you have??? work on you 60 foot. you need to work on the suspension . look at you torque converter it may be going bad . if you drive this on the street go with 430

I guess I don't know what cr is No I don't drive it on the street and yes it is a solid cam

CR is compression ratio .on the intake i would look at a single plane or rpm air gap

Thanks it is supposed to be around 12.0 to 12.5:1 I am running a single plane high raise on it now But the question still remains what heads should I buy?

WHEN YOU CROSS THE FINISH LINE HOW MANY R.P.M.S. ARE YOU TURNING?

Hands down, AFR 195 heads, are the best flowing head out there for their size, and they should be a great flowing head for you. Go to their website and check out the 180's and the 195's.

www.airflowresearch.com