ARP Pro Series Head Bolt Kits
All Pro Series bolts are cold-forged to maintain molecular integrity, heat-treated prior to thread rolling and machining, and built to meet ARP's ZERO defect - ZERO failure quality standard. These head bolt kits are application-specific and engineered to provide the superior strength typically required for competition engines.
Pro Series kits are available in standard (8740) material with 190,000 psi tensile strength and proprietary (ARP2000) material with 220,000 psi tensile strength, as noted. Each bolt features a reduced wrenching hex or 12-point head with a wide-area flange, allowing for the use of larger diameter valve springs and eliminating the need for valve train removal during cylinder head retorquing.
Hardened parallel-ground washers are included in every kit, and most applications include undercut short bolts. These bolts help prevent head gasket failures by providing additional stretch to compensate for gasket compression.