Replacement recessed dome pistons for 3-5/8" Big Bore applications. Will fit 84-99 Evolution Big Twin models with S&S SuperStock heads only and 3-5/8" bore cylinders in combination with 4-1/4" (5.375" cylinders, 9.4:1CR), 4-1/2" (5.500" cylinders, 9.8:1CR) and 4-5/8" (5.565" cylinders, 10.1:1CR) strokes. S&S tolerance recommendations: Close fit .0015" to .002". Loose fit: .003" to .004". All pistons include wrist pins, wrist pin clips and piston rings. 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. It is of importance that a knowledgeable mechanic will install & make adjustments as required. The rider must follow standard break-in and riding procedures for overhauled engines.

Fits: > 84-99 3-5/8" big bore Evo B.T. with S&S SuperStock heads and 4-1/4" (std), 4-1/2" and 4-5/8" stroke flywheels