Crankshaft Pulley, Billet, single groove, 30% reduction, SBC, short water pump Machined from the highest grade aircraft billet Aluminium for maximum durability Deep precision machined grooves ensure belt retention even during extreme changes in engine RPM When crankshaft and water pump pulleys are used together, water pump speed is reduced by approximately 30% Hard-coat anodized for extended life Uses 36° x 17/32 wide belt