..........power expectations........

Why not get a set of 273/318 heads and have either 1.88" or 2.02" intakes and 1.6" exhaust valves in them and port them...

Then you will increase the compression about a point without having to change pistons.

Then upgrade the cam.

Why throw away a good 360....

Are you saving the original 360,for future use Kimmer? I still like the Magnum., bolt & play.

FWIW : the basic year Magnum you have: is the 300 horsepower M/P crate mill. Same damn long block, add a carbed intake.