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. The solution? ARP quality. ARP rocker studs are concentric within .005 T.I.R. thread pitch to thread pitch. 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. These Pro series rocker arm studs are from premium grade 8740 chrome moly steel and heat-treated to a tensile strength of 200,000 psi. ARPs patented Perma-Loc adjusters (available separately) should be used, not OEM-style self-locking nuts. It is highly advisable to determine what the optimum rocker arm stud length is for your particular application. This is especially true when "long" pushrods and valves are employed -- you should raise the "installed height" of the rocker arm to compensate for the longer-than-stock components. The dimensions for these studs are: 2.000 overall stud height, .820 screw-in thread depth, .700 adjuster thread depth, 7/16-20 shank diameter and thread, and 7/16-14 base diameter and thread.