Buy new pistons and rods. It is cheaper to buy new rods then to have them resized and new piston material is far better then the old pistons you removed. The same with heads . Its cheaper to buy heads then to have yours redone. Unless you have a good running motor you just want to refresh for originality. My son has a engine machine service shop. He loses money when giving this advise but is honest when asked.
The rotating assembly is the heart of the engine. When it fails the arms, legs and everything attached usually get destroyed with it. $$$$$,!
You cannot make perfume out of **** and make it smell like a rose. Unless you take the advise from someone who's **** doesn't stink. Rotating Assemblies are the way to go. Just make sure your block is good. Magnaflux, line bore, and deck surface. then Clean, clean, and clean again.