ARP 1543604 High Performance Series Cylinder Head Bolts, Hex Style, For Select Ford Small Block Applications High Performance Series cylinder head bolts are a premium replacement for OEM fasteners Bolts are 180,000 psi, which is 15% stronger than Grade 8 hardware Wide area flanged head eliminates the need for valve train removal to facilitate cylinder head retorquing Features reduced wrenching hex style heads Comes complete with hardened parallel-ground washers