mild 360 rebuild questions

It would need boring and honing, the crankshaft checked and possibly machined. I would balance it if you go with different pistons. It likely won't need line boring, but it can be checked.
What is the head chamber cc? Then figure out what piston hight you need for proper compression.
Once you know these factors, you can order parts.

Or if you really want to do it cheap, check the bores, light hone, new rings, bearings, gaskets. It must be in pretty good shape with 140 psi.