This 124" big bore/stroker Hot Set Up Kit® transforms a stock engine into a 124" monster. This kit includes S&S 4-1/8" bore pistons, big bore cylinders finished in wrinkle black powder coat, a dynamically balanced 4-5/8" stroke three piece flywheel assembly complete with S&S heavy duty connecting rods and intergal mainshafts, S&S 640 gear drive Easy Start camshafts, S&S chromoly steel adjustable pushrods, S&S premium tappets,S&S Super Stock 91cc cylinder heads. When installed the kit yeilds a 124" engine with a compression ratio of 11:1. Although the engine is .960" taller than stock, there are no frame clearance problems, and a stock EFI Throttle body will fit because the manifold mounting surfaces of the heads have been specially machined to fit a stock length manifold. No fuel or ignition system is included. However, for the best results, a larger EFI throttle body, performance intake and performance exhaust are recommended. The EFI system must be recalibrated. Although not mandatory, we recommend adding an oil cooler to bikes ridden in warmer climates. S&S does not recommend compression ratios higher than 10:1 for Tri Glide® or other three wheel models (including conversions) due to extra loads caused by the lugging nature of these bikes. Detonation and subsequent engine damage may result.