It is for good reason that virtually every top professional engine builder relies on ARP Pro Series head studs for their all-out competition powerplants. Simply stated, there's not a better stud setup on the market today. ARP uses a premium grade 8740 alloy that is rated far superior to aircraft quality. Then, each stud is placed vertically in special racks and precisely heat-treated to 200,000 psi. 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 (a very common industry practice). You won't find a better quality stud on the market from any other source.