The BC 300M alloy MOAR design rods are intended for those making in excess of 2000whp and do not want to run an aluminum connecting rod. 300M material delivers a higher tensile strength (305,000 psi) than traditional 4340 steel (270,000 psi) with the additions of vanadium and copper as well as increases in silicone and molybdenum. The fatigue strength and tensile stress characteristics of 300M is the reason why it is the steel alloy of choice for aircraft landing gear. Features ARP's premium 3/8" 625+ Custom Age fasteners for added peace of mind.