2JZ ARP Head Studs 203-4205
ARP uses premium grade 8740 alloy that is heat treated to 200,000 p.s.i. 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. ARP studs are thread rolled after heat treat which gives them about 1000% better fatigue strength than studs that are 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 well worth the extra effort.