ARP Custom Age 625+ VQDE, VQHR, VHR, VR30 Head Stud Kit In-stock and very limited quantities ARP's Custom Age 625 Plus material is newly formulated super-alloy demonstrates superior fatigue cycle life, tensile strength, and toughness. ARP Custom Age 625+ provide complete resistance to atmospheric corrosion and oxidation making it an optimal choice for big builds requiring head clamping force experienced with no other hardware. ARP has been on the forefront of premium and unsurpassed manufacturing and testing for fasteners with Custom Age 625+ Hardware. Features Yield Strength: 235kpsi to 255kpsi Tensile Strength: 260kpsi Benefits No Modification to your cylinder head or block is required as these are a direct drop-in replacement for the OEM head stud! 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. This procedure ensures complete heat penetration and the results are far superior to those lesser quality studs from other manufacturers who just dump pieces in a basket and hope for the best. Following heat-treat, each stud is center-less 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 center-less ground; the material is thread rolled in bar stock form (mostly before heat-treat, when the material is easier to machine). 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% (that's ten times) better fatigue strength than those studs that are threaded prior to heat-treat (a very common industry practice). 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 mostly 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, ARP Head Stud/Bolt Kits are the best on the market today, and the favorite of leading professional engine builders in all forms of racing.
