crankwalk is luck of the draw....err...lack of luck of the draw perhaps....anyway, i had it happen to me, and was only running a 2100lbs clutch, try not to really let it bother you, if it happens, it happens, you should always have some money put to the side anyway, if something does occur, purchase a 6 bolt short block and go through the magnus method of swapping it, however i dont think you should be sweating it till ya see signs of it