ARP main studs are manufactured from 8740 chrome moly steel, heat-treated to 200,000 psi tensile strength, and precision J-form threads rollad after heat-treat to create a fastener that has threads 2000% stronger than others. Reduce crankshaft flex and main cap fretting with these premium quality main studs. Don't settle for anything less than the best! Main Studs Key Features: •Premium grade 8740 chrome moly steel •200,000 psi tensile strength •J-form rolled threads •Come with parallel washers and nuts All kits come complete with hardened parallel-ground washers and aerospace quality nuts.