ARP 250-6301 6.0|6.4 Powerstroke Rod Bolt KitARP Pro series connecting rod bolts are precision CNC-machined to exacting specifications and designed for optimum reliability. They are heat-treated and threads are rolled to provide up to ten times more fatigue strength. This makes them far superior to standard OEM fasteners in terms of durability, and fully capable of handling the extra stress of high-combustion engines. A premium grade 8740 alloy chromemoly steel is used to manufacture ARP High Performance connecting rod bolts. This material is heat-treated to provide a tensile strength in the 200,000 psi range. Which is substantially stronger than the OEM bolts. Cycle testing shows ARP High Performance rod bolts to be nearly five times more reliable than stock bolts.