ARP main studs eliminate main cap walk and fretting as well as protecting the threads in your engine block. All kits come complete with hardened parallel-ground washers and high quality nuts. Manufactured from 8740 chromoly steel, heat-treated in house to 200,000 p.s.i. tensile strength and precision J-form threads rolled after heat treat to create a fastener that has threads 1000% stronger than OEM produced studs. A must for high horsepower, high rpm engine applications