The article I participated in with Steve Magnate in Mopar Muscle and Hot Rod had a head gasket failure as the engine approached 200 HP. That's probably not too shabby, but if that's to be an expected issue at that HP range, how long can it live at say, 180 HP, if it's that close to a failure point...? It probably could have also failed in the 180 HP range if it had been given enough time.