These Ford Racing 5.0L Modular Boss 302 alternator kits include special high performance components as used on the production 2012 Mustang Boss 302 and are designed to operate at much higher rpm. The alternator uses a one - way clutch to prevent belt hop - off during upshifts. The included tensioner has higher tension for better belt control, and the larger diameter pulley slows down the armature speed, reducing drag and parasitic HP loss.