160 psi is what compression ratio
 

My vortec sbc 355 has 160 psi compression. what does this work out to? Is it about 9 to 1?

Thanks

Just trying to guess horsepower

Its not thet easy. The intake closing point on your cam has a lot to do with it. If its a stock marine cam, then yes, anywhere from about 8.8 to 9.3 static compression would be my guess.

Yea, like he siad. Cam overlap and timing really affects cranking compression.