To maintain a reputation for "zero defects", ensure optimum quality control, and produce fasteners of exceptionally high quality, ARP controls all aspects of the manufacturing process, performing all operations in-house where they can be closely monitored. ARP takes extraordinary steps to produce the very finest products of their kind on the market today. These High Performance series cylinder head bolts are a premium replacement for OEM fasteners. They feature a reduced wrenching hex and wide area flanged head that eliminates the need for valve train removal to facilitate cylinder head retorquing. The bolts are 180,000 psi, which is 15% stronger than Grade 8 hardware, and they come complete with hardened parallel-ground washers. This kit is designed for select Chevrolet big block applications (Brodix aluminum head, -2, -4, Canfield).