Overheating issues with remanufactured 360

FIRST thing to do is determine where the timing is and what the distributor curve is

SECOND thing to do is investigate the cooling system. Did it cool the 318 OK? Any "overhead" with it?

Thermostat? try a good name brand stat, 180

If none of that works degree the cam. You can "get into" the engine good enough to see how "close" it might be without tearing the engine clear down.