HI, I have a 79 350 thats all rebuild and in the car. I built my short block with a egal crank chevy stage 2 rods and speed pro flat top hyper pistons. the block is bored .060 over if that makes a differnece. My pistions are supposed to have a 9.67 compression with 64cc chamber. My friend keeps telling me my cars going to have no power b/c hes running 10:1 compression. Im going for 450hp and the machine shop told me I would make it with my 245 duration cam with 510 lift. Now how much Hp difference would it make if I would of did a 12:1 or say 11:5 compression. What would the hp difference be? If its big Im willing to change but I have every thing balence to these pistions and engine is built and haven been ran yet. Whats the highest compression I can get in a flat top pistion.
Let me know what you guys think.

 

I can't see what heads you're running there? 64cc chamber and...?

What's the deck height, measured?

Assuming iron heads, anything over 10.5:1 or so (with that giant cam) won't run well unless you're mixing your own race fuel. If you plan on driving it on the street i'd forget about any higher.

Which cam do you have? Part number and brand?

Flat tops in a 350 would max out at ~10.3:1 or so, with a 64cc head. That's exactly what I have.

 

what are your heads made out of, that limits your compression due to cooling

 

they are aluminum votec style.