Fitment Notes: ARP Custom Age 625+ Head Stud Kit - 01-16 GM Duramax 6.6L LB7/LLY/LBZ/LMM 2500/3500 incl. Kodiak/Topkick C4500/5500 - 230-4202 

With performance enthusiasts adding increasing amounts of turbo boost to diesel applications, ARP has provided an extra measure of security in the form of extra-strong head studs manufactured from the firm's proprietary Custom Age 625+ material that has a minimum rating of 260,000 psi tensile strength. They are engineered to provide the clamping force required to keep cylinder heads from lifting due to exceptionally high combustion pressures. The stud kits include heat-treated chrome moly steel nuts (12-point) and parallelground washers. The studs are manufactured in ARP's Santa Paula, CA plant, with threads rolled after heattreat 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. 

ARP 230-4202 Kit includes:
Chrome moly steel 12-point steel nuts
Parallel-ground washers
Centerless-ground head studs