ARP CA625 Diesel Head Stud Kit 98.5-23 Dodge 5.9L/6.7L Cummins 247-4204

More and more Diesel Power Products customers are running large single turbos or compound turbo set-ups. Many of these turbos are capable of upwards of 50PSI of boost pressure with the right fueling. At these pressures the stock head bolts on our light duty diesel trucks are prone to stretching which can lead to head gasket failure. Head to block sealing is critical and that's where ARP Diesel Head Studs come in.

You should know that ARP uses a premium grade 8740 alloy that is rated far superior to "aircraft" quality. Then, each stud is precisely heat-treated to 220,000 psi. Following heat-treat, each stud is centerless ground to make it as close to perfectly concentric as possible. This procedure involves about ten very slight cuts and results in an exceptionally straight part. It's important to note that lesser quality studs are not even centerless ground”the material is thread rolled in bar stock form (mostly before heat-treat, when the material is easier to machine). ARP studs are thread rolled after heat-treat, which gives them about 1000% (that's ten times) better fatigue strength than those studs that are threaded prior to heat-treat. Because 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 head studs.

What really is the difference between a head stud and a head bolt you may be wondering. From the factory, all engines have head bolts. As nearly anyone has seen, a œbolt is a threaded shaft with a hexagonal head attached. These bolts thread into the respective hole and the bolt head is then torqued down on the head(s) with a great deal of the force being applied to the thread themselves. In contrast, a œstud is only the threaded shaft that is first installed into the block. Once the stud is installed onto the block, then the head gasket and head are placed. Finally, the head stud washer and nut are placed and torqued. Due to the change in orientation of where the force is applied, a head stud will not stretch as a head bolt will commonly do, as well as the superior metals used to make ARP head studs compared to stock head bolts.

While most diesel performance enthusiast know ARP for their heads studs, they actually have a wide range of fasteners available that are far superior to their stock counterparts. From harmonic damper hardware to rod bolts, flexplate bolts, and so much more. With ARP, you can rest assured that youre installing the best hardware on the planet.