Nissan RB DOHC 1/2" ARP Head Studs AR999-4209
AR9994209 or 9994209 NISSAN RB DOHC 1/2" HEAD STUDS ARP fasteners fits Nissan RB20DET, RB25DET, RB30ET 1/2" Stud With Twin Cam Head & CA18DET.
This kit requires modifications to your engine as the OEM Holes are not 1/2" Diameter
It is for good reason that virtually every top professional engine builder relies on ARP Pro Series head studs for their all-out competition powerplants. Simply stated, there's not a better stud setup on the market today.
For openers, ARP only uses premium grade 8740 alloy and a proprietary ARP2000 alloy that are rated far superior to "aircraft" quality alloy steels. Secondly, each stud is placed vertically into special racks and precisely heat-treated to 190,000 psi for the 8740 material and 220,000 psi for the ARP2000 material.
This procedure ensures complete heat penetration and the results are far superior to those lesser quality studs from other manufacturers who just dump pieces in a basket and hope for the best. 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 evencenterless ground - the material is thread rolled in bar stock form (mostly before heat-treat, when the material is easier to machine).