I had a motor built for me a few years ago, and I can't remember what the engine builder told me was the ratioAny way to determine?

 

Yeah, pull the heads, unless you know the piston thats in it and the cc of the combustion chamber of the heads. There are alot of variables. but no easy way other than to pull it apart.

 

Worn rings, bad valves or valve guides and even different cam grinds can easily change a compression test result so there's no way it can be used to determine a compression ratio.

As mentioned above, without knowing piston design and combustion chamber size, it'll have to be torn down to find the ratio.

 

Not to mention it's pretty likely that no two gauges will give exactly the same readings either.

 

383,5.7 rods,afr 195 street heads,74 cc combustion chamber, xfi 280 cam,,srp flat top -5cc. the block was "4 cornered"? Don't remember how far he left the pistons in the hole. An approximate CR from this info guys? Oh the engine has about 1-2 "light break in" hours on it

 

What head gasket?

 

I think I remember him saying 041?