The ARP 250-6304 Connecting Rod Bolt Kit is engineered for Ford 6.7L Powerstroke engines. These connecting rod bolts are manufactured in California using ARP's exclusive ARP 2000 alloy. The threads on each bolt have been rolled after being heat-treated to increase strength and black oxide coated for protection and longevity. These 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.