MCS-531778 - Forged piston set. For 41-78 1200cc (74") Knuckle; Panhead; Shovel and 1340cc Shovel. Fits engines with stroker flywheels and stock 3-7/16" (1200cc) or 3-1/2" (1340cc) cylinders with stock 5.330" length. Compression will be approx 8.4:1 with 4-1/2" stroke

Fitment:
41-84 B.T. with 84" (4-1/2" stroke); 86" (4-5/8" stroke) & 88" (4-3/4" stroke) engines (NU)