Service part for Panhead and Shovelhead engines This grind is a dead-on reproduction of the stock cams used in 1948-84 Big Twin, perfect for repair and restoration of 74" and 80" engines Available for generator engines with inner cam bushings or inner cam bearings, and for early and late alternator engines with different cam gear pitch diameters Note that the front and rear cylinders have unique timing specs Bolt in Hydraulic tappet required