These camshafts are for 1954–'84 big twins with either the Hydraulic Conversion kit or the Cylinder Head Replacement kit for panhead engines. They are also replacement parts for P-Series and SH-Series engines. Since these kits and engines include 1984–'99 style hydraulic lifters,the larger late style roller diameter requires that cams designed for 1984–'99 models must be used to achieve correct valve timing. When choosing a late style cam for this type of engine, be aware that, due to the approximate 1.5:1 rocker ratio of most aftermarket rocker arms for shovelheads, the total valve lift will be reduced by about 9% from the specified value. The specification chart shown here shows specs as used in a panhead or shovelhead engine.
In order to achieve stated timing specifications, these cams must be used in engines with 1984–'99 style tappets.
These cams should not be ordered as replacement parts for early S&S SH-Series engines, or for any shovelhead engine equipped with stock valve train. For replacement parts for these engines, select stock style cams and tappets