in reply to bubba68ss answer on original post.Idont know what kind of pistons i have{i think flat tops} but i have 2.02/1.60 corvette double humped headsagain the compression test shows 145 lbs.CO Ithat info can help on my original question,I would appreciate any feedback.thanks sasquatch58...

Cranking compression can't tell you what the CR is. My engine has 10.5 and cranking compression of 165psi. With a different cam, or a weaker or stronger battery the reading would be different.