ARP Head Studs G1

Obtaining the optimum cylinder head-to-block sealing is especially critical in small displacement engines employing high compression pistons (like the ones in a Cooper) or power adders like a high flow head and your Cooper S supercharger. That's why ARP head studs are popular among leading Sport Compact/Import racers.

You should know that ARP uses a premium grade 8740 alloy that 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 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. You will also note that ARP offers specially undercut studs for several engines. This procedure (done only to the shorter studs) equalizes the "stretch" of the studs, which makes for a more consistent clamping force. This helps prevent blown head gaskets and assures optimum sealing!

Premium parallel ground washers and assembly lube are also included with each kit.

Note: You will need a 12 point 12mm socket, 4mm allen socket, extensions, & 3/8 drive torque wrench.

Instructions Download