An S&S 103" 3-5/8" Sidewinder big bore stroker kit is an economical route to a larger displacement engine. This kit contains nearly everying needed to take a stock 74" or 80" HD shovelhead engine up to 103" displacement. This kit includes S&S 3-5/8" bore high tensile cast iron Sidewinder cylinders and forged pistons with wristpin and rings, a 5" stroke small diameter dynamically balanced S&S flywheel assembly, complete with S&S heavy duty connecting rods and mainshafts, S&S stainless steel head bolts, base nut, S&S adjustable chromoly steel pushrods, head gaskets, base gaskets, exhaust gaskets, and an S&S heavy duty top motor mount. Compression is 9.7:1