S&S Cycle 557 Easy Start Cam Kit For Harley Twin Cam Features: Bolt-in - no headwork Start any engine with a stock starter Save your starter and battery Reliable - tested for 100,000 accumulative starts and over 150,000 road miles without breakage or compression release failure Automatic - no buttons to push Optimized for heavy bikes needing lots of bottom and mid-range performance Can be used with some engines with stock pushrods, springs and lifters high-lift valve springs may be required for some applications Made in the USA Specs: Intake open/close: 6/27 Exhaust open/close: 39/12 Intake duration: 212 Exhaust duration: 231 Lift: .557