The ARP LSX/L99 Head Stud is designed to withstand high cylinder pressures and the most demanding conditions. This premium grade 8740 series aluminum alloy is rated far superior to “aircraft” quality, then each stud is precisely heat-treated to 200,000 psi. Following heat-treat, each stud is centerless ground to make it as close to perfectly concentric as possible. This procedure involves about ten very slight cuts and results in an exceptionally straight part. It’s important to note that lesser quality studs are not even centerless ground the material is thread rolled in bar stock form (mostly before heat-treat, when the material is easier to machine).
ARP’s Advantage studs are designed to stretch less than conventional studs, so they keep the head gasket where it should be. You’ll also find that they have approximately 1000% better fatigue strength than those studs that are threaded prior to heat-treat, and offer specially undercut studs for several engines. This procedure (done only to the shorter studs) ensures a more consistent clamping force, preventing blown head gaskets and optimum sealing!