[Stock72Nova]

I need a compression ratio estimate. I have a 30 over block with trw flat top pistons, and 64cc chamber heads and a 400 crank roughly what compression ratio would that give me? thanks

 

[Ryan V64SS]

Too much for pump gas!

 

[Ryan V64SS]

What size bore?

My 406 with flat tops, 74.5 cc heads comes out at 10.5 to 1 but I am running a really big solid roller so pump gas is not going to be a problem.

 

[Stock72Nova]

30 over stock 350 bore whatever that would be Ill be running alluminum heads so it should help with heat disipation and detonation.

 

[bigbadbp7]

my 350 with flat tops and 64c chambers 10:1

 

[Ryan V64SS]

400 crank will be well over that 10 to 1 of your 350 with the same heads.

 

[supernovanator]

30 over stock 350 bore whatever that would be Ill be running alluminum heads so it should help with heat disipation and detonation.

http://www.csgnetwork.com/compcalc.html

A 350 had a 4.000" bore. You have a 383, which is a +.030" 350 with a 3.75" stroke crank. Typical Mr. Gasket steel shim head gasket is probably .015-018" and I have no idea what cc to take off for valve reliefs. I just put -4cc in there. Also no idea about your motor's piston-to-deck. Just random guess and it is around 11.4

 

[6NOVA4]

check out this comp ratio calculator.

http://kb-silvolite.com/calc.php?action=comp

need to know your piston cc and the bore size of your gasket and compressed thickness.

assuming zero deck a flat top piston with a 400 crank is 11.2 to 1 with a 64 cc head

 

[Stock72Nova]

cool thanks guys I was hoping to be in the 11's or 12's

 

[74 hatchback]

Im guessing 11.5 to 11.75 based on all info.

 

[jer66nova]

Calculator

Go to eagle products.com have calculator with all dimensions bore stroke deck height cyl head cc volume head gasket thickness press enter it will tell you what you need to know web site is eaglerod.com

 

[SMLBLK66]

its going to be right around 11-1 depending on your gasket. and if you have a two valve relief or four. but either way it will be close to that. no more than 11.4-1 at most.