This 106" big bore Hot Set Up Kit is easy to install. No machining or rebalanceing is required, and the engine does not need to be removed from the chassis. This kit includes S&S 3.927" bore pistons, big bore cylinders finished in silver powder coat, S&S 585C chain drive Easy Start camshafts, S&S chromoly steel adjustable pushrods, S&S high performance tappets. The resulting 106" engine has a compression ratio of 10.2:1, and is stock height, so there are no frame clearance problems, and a stock EFI Throttle body will fit. No fuel or ignition system is included. However, for the best results, a larger throttle body, performance intake and performance exhaust are recommended. The EFI system must be recalibrated.