Designed to replace the original low carbon GM part, the ACG-020 is made from billet 4140 steel and heat treated with the austempering process. Shot peening is included. Journals for pivot bushings have a 7/16"-20 thread in both ends. The lower control mounting surface is raised approximately 1/8" for a slight improvement in the roll center. Normally used with ACG-012 upper Control Arm Shaft. Spherical bearing and hardware kit is available from ACG Enterprises - 405-634-8656.