Andrews products grinds its cams using a computer with cam design capabilities This superior technology gives the utmost in both performance and reliability Only the best alloy steel billets and heat-testing processes are used The power in a Harley Twin Cam engine is completely released only when superior Andrews computer-designed high-performance cams are installed Bolt-in cam with more power through the entire rpm range Uses stock springs; Note: Installer must check coil bind, valve-to-valve clearance and valve-to-piston clearance