Holed piston problems are usually caused by detonation. Detonation is caused by overheating, over advanced ignition timing or too low octane fuel. Not likely to be a problem with the fuel unless someone's shaved a lot off the head. But you know you had the overheating, Fixing that has to be a good thing, I would check the ignition timing when the motor's back together too.
Good luck with the truck, Stuart.
