ARP 135-3609 Cylinder Head Bolts Kit for Mark V IV Chevrolet Big Block w/ Brodix HeadsFastener Style: Bolt Undercut Stud: No Head Style: Hex Fastener Material: Chromoly Fastener Finish: Black oxide Washers Included: Yes Cut to Fit: No These ARP High Performance series head bolt kits are tough! They are rated at 170,000 psi 15 percent stronger than Grade 8 fasteners. They come available with hex heads or reduced wrenching 12 point heads that eliminate the need for valvetrain removal when re torquing cylinder heads.