HDX Clutch sets are the performance upgrade for your daily driver/hot rod. Pressure plates feature increased clamp loads and our 300 Series organic clutch disc. 300 series consists of steel backed organic facing material that greatly increases rotational strength, and an eight spring center hub for excellent shock absorption. Use HDX sets for cars with bolt on mods and mild power enhancements, for street or strip. RAM-309M Brand: RAM Automotive Co. Product Line: RAM 300 Series Clutch Discs Input Spline Quantity: 26 Input Shaft Diameter (in): 1 1/8 Disc Diameter (in): 10.500 Disc Material: Organic Disc Style: Sprung hub Quantity: Sold individually. Clutch Disc, Organic, 1 1/8 in. Dia. 26-Spline Shaft, 10.5 in. Disc Dia., Buick/Chevy/Oldsmobile/Pontiac,Ford.