Short, lightweight pumps dissipate heat more rapidly and equalize water flow to both sides of the engine. Billet steel fan hub and bosses for external water lines are included. Note: ALL31100 pump is not recommended for use with mechanical fans over 5000 RPM. Above this RPM, use the ALL31105 pump with a 3/4" bearing. Water pumps may need to be clearanced for use with 8" dampers.