S&S Cycle 91-9126 Sidewinder 93" Big Bore Stroker Engine Performance Kit 8.5:1

The S&S Cycle Sidewinder 93" Big Bore Stroker Kit is a comprehensive engine performance package designed to dramatically increase displacement in classic Shovelhead-powered motorcycles. Built with an 8.5:1 compression ratio and a 4-1/2" stroke, this kit delivers a significant power and torque upgrade over the stock 74" or 80" engine configuration.

The Sidewinder kit centers around S&S's high tensile, cast iron Sidewinder cylinders bored to 3-5/8" (3.625"), paired with forged pistons complete with wrist pins and rings. The dynamically balanced S&S flywheel assembly—pre-assembled with heavy-duty connecting rods and mainshafts—ensures smooth, reliable operation at higher displacement.

Kit Includes:

• 3-5/8" (3.625") bore high tensile cast iron Sidewinder cylinders
• Forged pistons with wrist pins and rings
• Dynamically balanced S&S flywheel assembly
• S&S heavy-duty connecting rods and mainshafts
• S&S adjustable chromoly steel pushrods
• S&S stainless steel head bolts and base nut
• Head gaskets, base gaskets, and exhaust gaskets
• S&S heavy-duty top motor mount

Important Installation Notes:

• Stock cases and heads must be bored to accept the larger 3-5/8" bore cylinders
• Stock cases must be cleared for the crank pin nut
• Stock flywheels must be re-balanced if not using the included S&S flywheel assembly
• An S&S intake manifold must be purchased separately due to the increased cylinder length

Proudly made in the U.S.A., this kit is engineered and built to S&S Cycle's exacting performance standards—making it the definitive big bore stroker solution for Shovelhead engine builds.