ARP ROCKER ARM STUD KIT - LS - NON-ADJUSTABLE - 234-7207 ARP Pro series rocker arm studs are ideal for competition applications. They are made from 8470 chromoly steel and are heat-treated to 200,000 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, these studs are more resistant to flex and will provide a more positive seating. Pro Series rocker arm studs were designed for use with Perma-Loc adjusters (not for use with OEM-style, self-locking nuts).