TMS L19 Main studs hold your crankshaft in place. As you make more power, and rev higher than your engine was designed to rev from the factory in stock trim, you start to push the limits of the factory fasteners.
Factory fasteners were not designed for performance use. The material chosen by the Original Engine Manufacturer for your engine's factory fasteners was chosen to meet the criteria of a normally driven consumer vehicle at the provided stock horsepower and rev limit. The material is not optimum for a high revving, high heat, high power, race car.