S&S 509 Cam Kit For Harley Twin Cam Features: Available in chain drive and gear drive versions All chain drive cams include installation kit All gear drive cams include 4-gear set and installation kit Made in the USA 509 Cam Info: Originally designed as a bolt-in, high-torque cam for 88 motors with stock compression ratio Lower lift allows them to be bolted into some engines with stock valve springs, pushrods, and lifters high-lift valve springs may be required for some applications Compression releases are not necessary with this cam Great low and midrange torque Strongest from 1,000 Rpm-4500 RPM Intake open/close 18/18 Exhaust open/close 46/11 Intake duration 216 Exhaust duration 237 Lift .509