OLDSMOBILE 455 6.735 H-beam connecting rods are manufactured from aircraft quality 4340 chromoly steel. The rods are x-rayed and ultrasonically tested with all surfaces shot peened and stress relieved.         8640 ARP 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. WILL FIT LATE 400. (REQUIRE CLEVITE 542 HN NARROW BEARINGS FOR BETTER OILING)