ARP Rocker Arm Stud Kits | Multiple Chevrolet Fitments (235-7204)Rocker Arm Stud Kit by ARP 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