4 bolt mains, rights? I wouldn't mind relieving you of one of those engines.

My only worry is that detonation might have occured in other cyls as well, although probably to a lesser degree. So I'd probably want to inspect a few things, I'd hate to throw a new piston into #6 and find out later #4 had a cracked ring land. Dibs on one of those blocks Jason!! Take care.
Joe