A premium grade 8740 alloy is used by ARP, rated far superior to 'aircraft' quality, for their Pro Series cylinder head studs.
Each stud is precisely heat-treated to 200,000 psi in special racks to ensure complete heat penetration, placed vertically.
Unlike lesser quality studs, the studs are centerless ground to achieve as close to perfectly concentric as possible.
With such exacting tolerances, you will note that gaskets and cylinder heads literally glide into position and are perfectly aligned, which won't happen with inferior quality head studs.
After heat-treat, these studs are thread rolled, resulting in about 1000% (ten times) better fatigue strength than those studs threaded prior to heat-treat, a very common industry practice.
Although it costs more to do it this way due to tooling strain, the results justify the extra effort.
This cylinder head stud kit comes complete with conventional hex style nuts and premium quality parallel ground washers.
