Product Description40 Series Torque Converter Set3/4″ Bore Driven Clutch1″ Bore Driver ClutchIf you currently have a centrifugal clutch, you can upgrade by a going to a torque converter. Torque converters improve take off power, acceleration and top end speed on atvs, utvs, go-karts and other vehicles.Driven clutch details:Overall OD of pulley: 193mm [7.6″]3/4 BoreBuilt in 3/16″ keyReplaces 40/44 series models209133 209133ADrive clutch details:Outside diameter of “bell”: 144mm [5.68″]1″ boreBuilt in 1/4″ keyKnown to fit most 8hp-18hp engines with 1″ horizontal shafts with a 1/4″ keyway. Check pictures and measurements to be sure this is the correct clutch for your application.