I know the general rule where all cylinders should be with 10% of each other, what I cannot find on the net is what a good PSI for a heathly small block Chevy should be.

When my engine is warm with all plug wires off and throttle wide open I get to 150-160 PSI on all cylinders. What I don't know is how "good" this is. I know it means I have a healthy engine but I mean compression ratio wise.

The only clue I could find on the net is chevyhighperformance.com did a test on a small block and called 140psi "dismal" compared to the 190psi on another small block.

Basically what I am looking for is a rough estimate as to my compression ratio since I want to move from 76cc heads to 64cc heads. I am pretty comfortable there though since I have been helped by this board already in that area.

 

you can't really tell compression ratio this way because you are measuring cylinder pressure not the compression ratio. Those numbers sound good for an engine with a relatively big cam, cam makes the biggest difference while a difference between cyclinders ussually means bad sealing of valves or leaky rings.