ARP - Nissan RB Main Stud Kit

Torque Spec's:  Nuts, 60lbs stepped up in 3 equal steps (20/40/60lb steps) - Studs, threaded into block finger tight

8740: 8740 chrome moly is seen as a good tough steel, with adequate fatigue properties for most racing applications, only if the threads are rolled after heat-treatment, as is ARPs standard procedure. Chrome moly can be heat-treated to deliver tensile strengths between 180,000 and 200,000 psi.
This ARP head stud kit uses premium grade 8740 chrome molly. Each stud is placed vertically into special racks and precisely heat-treated to 190,000 psi. This procedure ensures complete heat penetration and the results are far superior.

ARP2000®: ARP2000 is a steel alloy that can be safely heat treated to a higher level than 8740. While 8740 and ARP2000 share similar characteristics ARP2000 can achieve a tensile strength of 220,000 psi.

This ARP head stud kit uses a proprietary ARP2000® alloy that are rated far superior to aircraft quality alloy steels. Each stud is placed vertically into special racks and precisely heat-treated to  220,000 psi for the ARP2000® material. This procedure ensures complete heat penetration and the results are far superior.