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.