"Ran when pulled"

Tearing it down and rebuilding is always the BEST route. However, I believe the guy, that it ran good when pulled. the notches on the pistons are going in the right direction for the assembly of the motor. I sticking with my guess, that those are all factory pistons. But if you are going to add boost, then I would certainly do the bottom end. I would also do it with a forged crank..... from a 273, or late 60's 318 truck motor (easiest places to find a forged crank without breaking the bank).