It is for good reason that virtually every top professional engine builder relies on ARP Pro Series head studs for their all out competition power plants. Simply stated, there's not a better stud setup on the market today. For openers, ARP uses a premium grade 8740 alloy that is rated far superior to ""aircraft"" quality. Each stud is placed vertically in special racks and 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. It's important to note that lesser quality studs are not even centerless ground, the material is thread rolled in bar stock form. Because ARP studs are manufactured to such exacting tolerances, you will note that gaskets and cylinder heads literally glide into position and are perfectly aligned, something that won't happen with inferior quality head studs. ARP studs are thread rolled after heat treat, which gives them about 1000 Percent (that's ten times) better fatigue strength than those studs that are threaded prior to heat treat. It costs a lot more to do it this way, because it's tough on tooling, but the results are well worth the extra effort. You will also note that ARP offers specially undercut studs for several engines. This procedure (done only to the shorter studs) more equalizes the ""stretch"" of both studs, which makes for a more consistent clamping force and one that compensates for head gasket compression when the cylinder heads are installed. This helps prevent blown head gaskets, and assures optimum engine sealing! Premium quality heat treated 8740 chrome moly steel head stud kits are available for most every domestic and import applications. You won't find a better quality stud on the market from any other source. Look for ARP stamped on each stud as your assurance of quality. Clearly, they are the best on the market today, and the favorite of leading professional engine builders in all forms of racing.