4340 chromoly steel. Screw has oil hole drilled through the center for running a custom 'top-end lubrication through the pushrods' system. 3/8" ball end and 9/32"-32 threaded. Note: Specialty item. Designed for use with special JIMS tappets for top-end lubrication through the pushrods.
Fits: > 36-52 Knuckle, Panhead and all others, including Shovelhead and Evolution with special JIMS tappets
