ARP High Performance series rocker arm studs are ideal for ET bracket racing, limited rule oval track competition, and street use. They are heat-treated to 180,000 psi tensile strength. These studs are concentric within 0.005 T.I.R. thread pitch to thread pitch, which will give you more consistent rocker geometry. With an extra-large radius base, these studs 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).