These pro series rocker arm studs are ideal for competition use. They are made from 8470 chromemoly steel and are heat treated to 190000 psi tensile strength. These studs 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 with roller rockers and stud girdles.