Fitments
48-84 Big Twin with 3-5/8 big bore cylinders and strokes from 4-1/4" to 4-3/4" (88" to 98" engines)
Part Description
KB Performance, 3-5/8" big bore piston kit. STD
3-5/8" big bore piston set. Used with 3 5/8" big bore cylinders with 5.330" (stock) to 5.530" (+.200") length. Use with 4-1/4" stock stroke (88"), 4-1/2" (93"), 4-5/8" (96") to 4-3/4" (98") stroker flywheels. 10.0:1 CR. Piston weight 385gr. Piston pin weight 97gr. Head type: Dome / Dome -57cc. Compression height 1.285" / Bore 3.625" (3 5/8"). Stroke 4.250" to 4.750" (4-1/4" to 4-3/4"). Rod length 7.440" / Cyl. length 5.330" (Std) to 5.530" (+.200"). Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions. Note: 5.330" cylinders can be used with stock 4-1/4" stroke. Longer strokes require correct length longer cylinders or stroker plates to achieve the desired compression ratio. Note: In any and all applications the technician must be able to judge components for their suitability in combination with the other engine components, prior to installation.
