ARP has released Rod Bolts for the Mitsubishi 4B11 engine in the Evolution X ARP Rod Bolts are made of premium grade 8740 chrome moly steel and heat treated to a nominal tensile strength of 200,000 psi. Threads are rolled after heat treat to ensure optimum fatigue strength. They are far superior to OEM fasteners in terms of durability and service life and are fully capable of handling the extra stress of high combustion pressure engines.