ARP uses a premium grade 8740 alloy, rated far superior to 'aircraft' quality, for their Pro Series cylinder head studs.
Each stud is precisely heat-treated to 200,000 psi and placed vertically in special racks for complete heat penetration.
Unlike lesser quality studs, the studs are centerless ground to achieve near-perfect concentricity.
Due to the exacting tolerances in manufacturing, gaskets and cylinder heads align perfectly, which won't occur with inferior quality head studs.
After heat-treat, these studs are thread rolled, resulting in about 1000% (ten times) better fatigue strength than studs threaded prior to heat-treat, a common industry practice.
Although this method is more costly due to its impact on tooling, the results justify the extra effort.
This cylinder head stud kit includes premium quality parallel ground washers and compact 12-point style nuts for select Volkswagen applications (Golf/Jetta, 1.8L and 2L, 8 valve).
