71 dodge 360 running motor.

Scat cast crank kit should be sufficient for what you want. Balanced kit is the easy button, regular kit is cheaper but then you need to pay someone to balance the assembly. Supposedly the first couple years were thicker walls but there is always potential core shift to contend with so sonic checking is a good idea before sinking a bunch of money into the machine work. For your power level, as long as they aren't thin, any block should work.