Description: SB Chevy late model Vortec rocker arm stud kit Pkg: kit Pkg Type: skin Material_1: 8740 chrome moly Finish_1: black oxide Material_2: N/A Finish_2: N/A Origin: USA Category: Cylinder Head Product Line: Rocker Arm Kit Type: StudChevy late model Vortec V8. ARP 134-7201 Rocker Arm Studs. If you have ever installed a rocker stud into a cylinder head and watched it wobble as it screwed in you knew from the beginning that the rocker geometry was going to be inconsistent all over the place.ARP rocker arm studs are concentric within .005 T.I.R. thread pitch to thread pitch. They run-in straight and true. Lengths are exact designed to provide positive seating every time. An extra-large radius base offers greater resistance to flex. Available in both High Performance and Pro Series models. NOTE: Not to be used with OEM-style, self-locking nuts. To be used with ARPs patented Perma-Loc orShur-loc rocker arm nuts