Comes with camshafts and inner gears, this kit is designed for those who are replacing or upgrading an engine already equipped with S&S Cycle gear drive cams, and will be reusing the existing outer gears Installation kit 434-207 is not included but is recommended S&S Cycle Easy Start Gear Drive Camshaft Set is designed for the stock oil pump Easy Start Cams from S&S Cycle make hard starting obsolete for 1999-16 Twin Cams Gear drive version Start any engine with a stock starter Save your starter and battery! Reliable - tested for 10,000 starts and didn't even run the battery down! Automatic - no buttons to push Camshafts that exceed the limits of the stock valve springs require the use of special high lift springs Most S&S cams have higher lift than stock and are designed to take advantage of the extra flow of ported stock heads or S&S Super Stock heads Due to the high lift of these cams, S&S adjustable pushrods are recommended To get the best performance from a performance cam installation, a high flow intake and exhaust system is also recommended Quick installation and Easy Start Cams allow stock starter to start any engine Kit contains cams, gearcover gasket, cam bearings, and instructions 2005-up stock valve springs will handle camshafts with lift up to 0.585" If a camshaft with higher lift is installed, high performance valve springs capable of handling a greater lift must be used Cams with over 0.585" of lift will cause interference between the valve spring top collar and the valve seal with stock cylinder heads 635 Camshafts are High lift cams for modified engines with 106" or greater displacement and compression ratios between 10.0:1 and 11.0:1 Works well with stock, un-ported heads, but S&S Cycle CNC ported heads are recommended Best power from 3000-6000 rpm This is not a bolt-in cam set. High-lift springs and clearance checks are required