318 with 360 heads and compcam build help

You would do well to read a whole thread before jumping in at the end. There are many ways to gain compression, milling heads, head gaskets, decking a block, but if you are buying pistons anyway, you can skip all that and the headaches and expense that goes with it. You just have to do some research and figure the combination out. AFTER you decide how you want to use your car.
Exactly