Head Stud Kit - ARP - 5.9L/6.7L Cummins - CA625+ Extreme Duty
From FICMrepair.com

ARP Head Stud Kit: PN 247-4204 - CA625 Extreme Duty
Fitment: 5.9L / 6.7L - 24V Cummins (1998.5 and later)
Look at any NHRA top fuel, NASCAR, IMSA, Pro Stock, other high-end race engine, and you'll see the ARP logo on a whole lot of fasteners. If ARP bolts can hold together 3,000-hp top fuel engines, you can trust them to hold your high-performance street engine together.
Simply stated, there's not a better stud setup on the market today. 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 studs.
ARP's proprietary Custom Age 625 material has a minimum tensile strength rating of 260,000psi. They're engineered to provide the clamping force required to keep cylinder heads from lifting due to exceptionally high combustion pressures and centerless ground to make them as close to perfectly concentric as mechanically feasible. Lesser quality studs are not centerless ground, have nowhere near the tensile strength and formed from thread rolled bar stock (mostly done before heat-treat, when the material is easier to machine). ARP has earned their reputation for quality.