High Performance head bolts are available with a reduced wrenching hex
or 12-point and wide area flanged head that eliminates the need for valve
train removal to facilitate cylinder head retorquing.
All High Performance
Series bolts are 180,000 psi (which is 15% stronger than Grade 8) and kits come
complete with hardened parallel-ground washers.
All Pro Series bolts are cold-forged to ensure molecular integrity, heat-treated prior to
thread rolling and machining, and are rated nominally at 200,000 psi. ARP Pro Series head
bolt kits are application specific – designed for use with typically competition only compo-nents. These fasteners deliver superior strength and meet the ARP “ZERO defect – ZERO
failure” quality standard. Hardened and parallel-ground washers are included with each kit to ensure even load distribution and accurate torque readings. All Pro Series head bolts have a
reduced wrenching hex or 12-point head and wide area flange to eliminate the need for valve train removal for cylinder head retorquing and permits the use of larger diameter valve springs.
Most applications have undercut short bolts that can help eliminate head gasket failures through providing more “stretch” to compensate for the additional compression of gaskets.