S&S S&S, 640 cam for Evo Big Twin

Description

S&S S&S, 640 cam for Evo Big Twin

84-99 Evo Big Twin (NU)

.640″ valve lift. Big inch engines with 10.5/11.5:1 CR. Smaller engines with 11:1 to 12:1 CR. With lower TDC lifts, faster ramps and shorter duration it builds higher cyl. pressure and requires less CR and offers a more linear power delivery as the 631. Supplied with the S&S 124″ SSW+ engines. 3000-6000 RPM.