This seems stupid, but I just put my new heads on and they were 64cc vortechs and I had them milled .030. I heard this gets a 305 close to 10 to 1. My head gasket is a real thin stainless steel that said it was.020 thick which was the thinest I could get the not so smart parts guys to find.

Any good guess would be helpfull

 

need to know how much in or out of the hole the piston is ,the volumn of the dish or valve reliefs plus the volumn of the head to figure it

 

Well they are the stock pistons with the two small valve reliefs. They aren't full valve reliefs just the two half circles. The heads were 64 cc but I had .030 taken off of them to keep the compression close to stock which is like 9.3 to 1 i think.

 

I don't think the milling would drop more than a couple ccs, and the gasket will have dropped about half that. I couldn't see your compression being much higher than stock, if at all, unless milling reduced the chamber size more than I think.

 

the milling would have dropped you in the 59 or 60cc range.

easy formula to get you in the ball park of what your compression is....do a compression test...say you get a reading of 155 now devide that by 15.1 then subtract 1...this would give you a compression of 9.2 to 1.

Compression test / 15.1
-1 =
compression