Compression ratio?

[Domingo]

Im thinking of replacing the heads on my sbc 350 .30 over flat pistons with the 4 valve relive cuts. Should I go with a 64cc head or 72cc. For a daily driver

[mongocanfly]

the more compression you run the better your gas is gonna have to be...I would opt for the 72s....what other work has been done to the engine?

[Domingo]

Im just going to be adding a summit cam 1103

[Captainfab]

There are several factors that determine whether you can run heads with 64cc chambers. One is the timing of the intake valve of the cam you have picked? Second is how far down in the hole the pistons are? Third is what is the compressed thickness of the head gasket you will be using? What ignition system are you running? What octane gas would you like to run?

[garyd1961]

I would go with 64cc heads even if I had to run 93 octane gas. It makes a livelier motor but as others have stated there are more factors at play here.

[Domingo]

I guess I'm going to go with 72cc. Is not going to be a race truck Im just looking for a little more power and still get away with using cheap gas. I'm building the truck to be a daily driver

[geezer#99]

If you want that cam to work right then you want to get your compression up. The 64 cc heads will help do that depending on your deck height.

[Captainfab]

I just never understand what the statement "It's not going to be a race truck" has to do with not building an engine to get the most out of the combination of parts.

[Domingo]

What I mean it will never see a track. Im just want to drive it every day and dont want to build something that im not going to enjoy. Say a radical cam or something that only runs with premium fuel

[cadillac_al]

If they are aluminum heads you will be using a thicker head gasket. I would go with 64's for that reason alone. If they are cast iron heads with a shim gasket then the 72's would be fine.

[geezer#99]

Originally Posted by Domingo

What I mean it will never see a track. Im just want to drive it every day and dont want to build something that im not going to enjoy. Say a radical cam or something that only runs with premium fuel

If you want a dd and a motor you can enjoy then use the 72 cc heads but get a milder cam like the summit 1101. Slightly better than stock to match up to your slight increase in compression.