ARP 230-4201 01-13 (6.6L) Duramax 12 mm Head Stud Kit

ARP Pro Series cylinder head studs are cold-forged to ensure molecular integrity. They are heat-treated prior to thread-rolling and machining, and all ARP 230-4201 Head Stud Kits come complete with hardened parallel washers for even load distribution and accurate torque readings.

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 no 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 220,000 psi. ARP studs are thread-rolled after heat treatment, which gives them about 1000% (that’s 10 times) better fatigue strength than those studs that are threaded prior to heat treatment (a very common industry practice). You won’t find a better quality stud on the market from any other source.