ARP Pro Series ARP2000 studs are centerless ground, heat treated prior to thread rolling and machining, and are nominally rated at 220,000 psi. These fasteners deliver a 40% increase in tensile strength over the OEM Torque to Yield (TTY) bolts. All bolts are precision centerless-ground and thread-rolled to Mil-S-8879 specs. Each utilizes a black oxide finish that protects them from wear and corrosion. All kits come complete with hardened parallel washers for even load distribution and accurate torque readings.