Replace the original†3.00" supercharger pulley with our 2.80" overdrive pulley to add 2-3 lbs of boost†to your Shelby Mustang.† The kit includes a pulley hub machined from high-grade steel that presses onto the blower shaft.† The CNC-machined aluminum ring bolts to the steel hub using the supplied stainless steel fasteners, and this two-piece design makes subsequent pulley ring changes a snap. The steel hub is re-usable (unlike aluminum one-piece blower pulleys), and is black oxide-coated for long lasting surface protection.† The aluminum ring is hard-coat anodized in black to resist surface wear, and after anodizing the ring†is†pocket-milled for good looks.