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 studs are thread rolled after heat-treat, which gives them about 1000% (that's ten times) better fatigue strength than those studs that are threaded prior to heat-treat. Premium 8740 alloy studs heat-treated to 190,000 psi · 12-point nuts and undercut studs for easy installation · Centerless ground for near-perfect concentricity Then, each stud is precisely heat-treated to 200,000 psi. That's why ARP head studs are popular among leading Sport Compact/Import racers. STM: ARP INDIVIDUAL HEAD BOLT NUTS | 11MM | 12MM | AUN12-1 | APN12-1 ARP Individual Head Bolt/Stud Nuts Following heattreat, 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. This procedure (done only to the shorter studs) more equalizes the stretch of both studs, which makes for a more consistent clamping force one that compensates for head gasket compression when the head is installed. ARP Head Studs ARP Cylinder Head Stud Kit, 12 Point Nuts, Chromoly, Black Oxide, 23 2084302 ARP Stud Nuts Fit type: Fits 1990-01 Honda Acura Integra B18A1 B18B1
