A complete performance clutch that is Big Inch motor capable? Your search is over. Installs in the stock clutch basket. The larger contact area of the competitor offers more friction for better maximum grip and is also generating less heat at the same effort. Included are two diaphragm clutch springs; of which the weakest is 20% stronger than stock. Special heavier and harder carbide ball bearings are used for improved durability. Includes installation instructions. Note: Compatible with up to approx. 120HP motors. See 590774 (7 balls) for up to 150HP or 590772 (14 balls) for up to 180HP for optional High Horsepower stronger clutch spring kits for more extreme engine builds.