I'm finishing up my GS850 piston mod on my 360 and, in the quest for high compression, made up a really thin head gasket for it (0.016"). Well, I guess I got too adventurous and now the pistons are hitting the head. I have to get them apart to get a thicker gasket in there, but they're stuck. It's a copper gasket with black RTV on both sides. I've tried the rubber mallet, beating it with a hammer and wood block, heating it up with a propane torch, and dissolving the RTV with ammonia (only modest success with that).
Any ideas where to go next? I know I could order up a thicker base gasket and call it a day, but at $40 a pop and a 2 week delay, I'd rather not if I don't have to.