Designed specifically for use with monster bores and ported heads (not recommended for stock bore engines). Improves cam timing accuracy and eliminates the stock cam chain. All-out horsepower cam for 124” and larger engines. Touring models require heavy duty valve spring kit. Requires Quikee adjustable pushrods with cover keepers. Kit includes outer drive gears, bearings, o-rings, and hardware. Tappets should be replaced every time that the cam is replaced, S&S suggest Precision Tappet set without HL2T Kit and Tappet Cuffs for M8 models.. Made in the USA.