Speedmaster's 6-71 Street Supercharger kits can give you 45-55 percent more streetable power. They feature double-pinned rotors (timed and clearanced after assembly), heavy duty front and rear bearing plates, and an intake manifold with a pop-off valve relocated to the back. The kits includes everything required to install, intake manifold, upper and lower drive pulleys, an idler pulley and bracket, a dual V-belt accessory drive pulley, a 3 in. Gilmer-style drive belt, and gaskets and hardware. Speedmaster also includes an adapter plate for two 4 barrel carburetors that is polished to match the supercharger.