Shaft Mount Ultra Pro Magnum Roller Rocker Arms for Chrysler B/RB V8 383-440 applications are made from SAE 8620 chromemoly steel. They are heat treated for maximum strength and stiffness to stand up to the demands of high performance applications. These shaft mount rockers contain proprietary bushing inserts and a unique oiling system that lubricates all the critical parts for a long lasting service life. Designed to handle roller lobes and higher spring rates, these Shaft Mount Ultra Pro Magnum Rocker Arms include a special adjuster that allows the use of conventional ball end pushrods. This is a complete kit; all bolts, shafts and spacers are included.