ARP 247-4204 Diesel Custom Age 625+ Head Stud Kit Dodge Cummins 5.9L/6.7L 24V '98-pres CA625+

ARP head studs begin by being placed vertically into special racks and precisely heat-treated. This procedure ensures complete heat penetration and is far superior to those lower quality studs from other manufacturers who just place the pieces in a basket. Head studs then move to a centerless grinding process to ensure that they are perfectly concentric. As many as ten separate machining steps are required to achieve this level of accuracy. The thread rolling operation is also done after the heat-treatment, which gives them about 2000% (that’s 20 times) better fatigue strength than lesser 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 worth the additional effort. Fasteners are then shot-peened to remove any surface irregularities and upgrade the overall external integrity. Finally, a metal finishing process is also performed in-house with a durable black oxide coating applied for improved corrosion resistance.