Reman DM Advantage On/Off SE 21 Fan Clutch Assembly, Kenworth/Caterpillar, 2.56" Fan Pilot, 3.50" Fan Bolt Circle, 8-Groove 7.23"O.D. Rear Pulley + 6-Groove 8.64"O.D. Front Pulley - A=7.23" A1=8.64" B=7.28" C=1.94" D=3.50" E=2.56" F=1.07" G=3.40" H=5.00"