That piston is for a closed chamber head run tight quench
if too much compression use a small dish - do not drop the piston down the hole or run a super thick gasket
If you have an open chamber head use one of the ones designed especially for those 360 heads
I like a ductile top ring
.002 .0025 should be fine except in a boat with cold water
do run gap recommended or better
run this way you should have more leeway with fuel and timing, less chance of detonation so what gas? 308 and EQ take less timing
detonation will kill anything and quench is more important than a little more compression
once you get the compression figured out and the rest of your build you can think of a cam
