ARP 3347203 Pro Series Rocker Arm Stud Kit, Chrome Moly Steel With Black Oxide Finish, For Select Applications Manufactured to high tolerances so they run-in straight and true, and the extra-large radius base offers greater resistance to flex Lengths are exact, designed to provide positive seating every time Made from premium grade 8740 chrome moly steel and heat-treated to a tensile strength of 200,000 psi; designed for competition applications Stud dimensions are: 2.100 overall stud height, .750 screw-in thread depth, .800 adjuster thread depth, 7/16-20 shank diameter and thread, and 7/16-14 base diameter and thread Designed for use with ARP's patented Perma-Loc adjusters, not OEM-style self-locking nuts