[steelcomp]

Mendez...
To really "know" your compression rate, you need to be able to measure your dome volume. This is the part of the piston that is above the top ring, including dishes, valve reliefs, pop up domes, etc. and you should consider the small space between the piston and cyl, above the ring to know your true ratio. Do you want to KNOW the CR, or do you wnat to have someone else tell you? Or just guess? Without knowing, you're guessing. It's easy. You should find out the exact (as close as possible) volume of your combustion chamber(s) as well. The head gasket mfgr can tell you the volume of the head gasket, since few are round. With this info, the formula is easy. If you're interested in learning how to "know" your engin and it's specs, let me know. I'd be glad to run you through it.