HARLEY Knucklehead Rocker Arm Set Fits 1938-1947 EL, 1940-1947 FL,

Machined Knucklehead rocker arm set. For use on the 1936-1937 valve spring cup and cap style covers where the rocker arms will be exposed. The outer diameter of the rocker arm is turned down to .80 inch on the center portion excluding the seal surface area on the pushrod side. This is for added clearance on 1938-1947 model lower tin covers. Sold as a 4 piece set. *NOTE: Right side of arm seal surface with ground outer diameter for single point seal contact. *NOTE: Before installation re-surface the head gasket by fly cutting or blanchard grinding. Re-check bore size STD .010 or .020 oversize. Rivet head that plugs holes from oil passages must be removed. FITS HARLEY: 1938-1947 EL, 1940-1947 FL,