360 compression issues. pick a piston??

Depends on what the rest of the car is built, gears, tranny, gas availability etc.
You can run fairly high compression with the right cam.
Also I am not familiar with the heads you are using, are they iron or aluminum?

A-833 OD , 3 55 gears. 91 octane gas.

Heads are 65cc closed chamber aluminum eddy copies.