Prevent premature head gasket failure! The Evolution Powersports XR Series CA-625 9mm direct replacement head studs are designed for those wanting the ultimate strength for 250-320 horsepower builds. These custom studs are designed to replace the factory head bolts and can be installed without having to remove the head. These 9mm studs are manufactured by ARP using their proprietary Custom Age alloy and are stronger than any other 9mm stud available anywhere.
Custom Age 625 alloy typically equals or exceeds the clamping force of ~2mm larger 8470 Chromoly fastener in a smaller package. When installed in 900 ACE engine where there is not much material in the block to enlarge the stud significantly, the 9mm Custom Age 625 is the ideal solution. These head studs will keep your engines head sealed for the boost pressure required to produce 250-320 horsepower.
Why the EVP XR Series CA-625 studs are superior to other studs on the market: