S&S Cams for Evolution Big Twin

S&S claims that their camshafts and other related valve train parts go through extensive dyno testing and usage on the track and street. After they are satisfied with the proven performance they carefully select and match various components to make the best kit combinations. Since many S&S cams are high lift types, they are available with a cam only or in a kit with a set of the appropriate S&S high performance valve springs. Refer to the Cam Specification Chart for cam timing and lift information.

Important information on S&S Evolution Style Cams in S&S Shovelhead Style Engines
S&S complete Shovelhead engines are equipped with special tappet guides designed to use S&S Evolution style tappets. This requires that an Evolution style cam must be used in these engines, or in any engine equipped with S&S Shovelhead style tappet guides. When choosing a cam for this type of engine, be aware that the timing specifications will remain unchanged, but that the total valve lift will be reduced by about 9% from the specified value, due to the difference in rocker ratios between Shovelhead and Evolution style engines.