Another 273 commando build .. This one will be a "BEAST"

Question: Are you wanting to save the pistons?? They may or may not be serviceable after you get them out. That said, take a piece of hard wood and a hammer, give the pistons a wack on the crowns and then from the underside, go back and forth like that, keep them wet with PB, Kroil. Patients is the key here.