How Much Damage could possibly occur..............

All depends, I agree with others that every catastrophe is different, haven't blown up a lot of motors, blew a hole in a piston on a 2.2, had the distributor in 180 degrees off, honed it, new (ebay) pistons, had the head checked out because of a piece of piston mushed into a valve, raced it 2 years, won 5 features, sold it to a 15 year kid and he won 5 features with it. Blew up a slant six(had an oil leak)rod through the block, broke the cam, the back of the cam went through the bellhousing. My brother blew up a built 360, took out almost the entire side of the block, think the heads were salvagable.