[Dusty]

I have broken about everything but a crank so I can't talk too much about that. This brings to mind the term endurance limit. The endurance limit is the amount of cycles at a certain level of stress that a part may have an infinite life span at. The text book definition is somewhere between 10^6 and 10^7 cycles. When you operate above that stress level the life span of the part is limited. In an IC engine the level of stress varies alot with any given part and becomes very complicated to calculate. In a drag racing engine parts are stressed beyond what would normally be qualified as "safe" in say a circle track engine. Due to the short duration of high levels of stress a part in a drag engine may experience it may last a while. At some point you must replace it and I don't think anyone can tell you when that will be. You either have to break it and everything else or replace it while the engine is still intact. I guess the best answer I can give you is if you think you have gotten your moneys worth at this point retire it to your drive in movie car.