I have found a great product in Sea Foam Deep Creep. The last one I had to beat apart was probably the worst one ever. A 396 Chevy. What's worse is, when I took the block in to have it check out, it was cracked in three places, so all that for nuthin.
Tell you how I did it though. I sprayed Deep Creep on top of the pistons and let them all sit a couple of days. Came back with a 2x4 and beat them with a sledge hammer with the 2x4 on top of the piston until they loosened up. Went through several 2x4s. I got them all out though.
I've even pressed them out before. I have a press now and if I ever have to do this again, that's what I'll do.
