ARP’s Custom Age 625 Plus material is newly formulated super-alloy demonstrates superior fatigue cycle life, tensile strength and toughness – with complete resistance to atmospheric corrosion and oxidation. ARP is the first to develop manufacturing and testing processes for fasteners with Custom Age 625+. Best of all, it is less expensive and expected to soon replace MP-35 as the material of choice in the high strength, super-alloy field. Typical tensile strength is 260,000 psi.
Because of the many head lifting issues on 4G63 blocks running in excess of 35+ PSI, a stronger stud needed to be manufactured to meet the demands of today’s top engine builders and racers alike. No Modification to your cylinder head or block is required as these are a direct drop-in replacement for the OEM head stud!