ARP High Performance series rocker arm studs are ideal for ET bracket racing, limited rule oval track competition, or street use. Made from 8740 chromoly steel and are heat-treated to 180,000 psi tensile strength, they are concentric within .005 T.I.R. thread pitch to thread pitch, which will give you more consistent rocker geometry. With an extra-large radius base, they are more resistant to flex and will provide a more positive seating. These rocker arm studs are designed to be used with Perma-Loc adjusters (not for use with OEM-style, self-locking nuts).