4340 billet, large radius snout. These cranks are designed for dune riding, short course and trails. If big power, two-step launch drag application, recommend the BC5932 EN40B material stroker cranks. The BC stock stroke billet cranks also do not require any heavy-metal to balance for aftermarket rods & pistons. All cranks are stress relieved, shot peened, magna flux inspected and nitrided (multi step heat treatment) for ultimate performance. Fully profiled counterweights are designed for reduced windage through the crankcase creating less oil resistance for better rpm potential. Requires internal balancing of the crank for operation. Add $100 for balancing.