ARP 98.5-2012 Cummins 5.9/6.7 Headstud kit
These ARP studs are rated at 220,000 psi tensile strength, and provide the clamping force required to keep cylinder heads from lifting due to higher combustion pressures. The studs are manufactured in ARP's Santa Paula, CA plant from proprietary ARP 2000 material, with threads rolled after heat-treat to provide optimum fatigue strength. They are centerless ground to assure perfect concentricity. The ends of the studs are broached to facilitate easy installation. This feature also enables the cylinder head to be removed in tight quarters. Also included in each kit are heat-treated, chromomoly 12-pt nuts and parallel-ground washers. They are black oxide finished for extra durability.
Instructions are included but here are a few added tips:
- It is recommended to tap the holes in the block with a bottoming tap before installing the studs. This will require a 6" long 12mm bottoming tap
- On most motors the rocker box needs clearancing for the rear center stud nut
- The longer studs go to the exhaust side of the head
