ARP uses a premium grade 8740 alloy, rated far superior to 'aircraft' quality, for their Pro Series cylinder head studs.
Each stud is vertically placed in special racks and precisely heat-treated to 200,000 psi for complete heat penetration.
The studs are then centerless ground to achieve near-perfect concentricity, unlike lesser quality studs.
Because ARP studs are manufactured to such exacting tolerances, you will note that gaskets and cylinder heads glide into position and are perfectly aligned -- something that won't happen with inferior quality head studs.
By being thread rolled after heat-treat, these studs have about 1000% (that's ten times) better fatigue strength than those studs threaded prior to heat-treat (a very common industry practice).
It costs more to do it this way, because it's tough on tooling, but the results are worth the extra effort.
This cylinder head stud kit comes complete with premium quality parallel ground washers and compact 12-point style nuts for select Toyota applications (4AG, 16 valve).
