Manley Pro Series connecting rods are forged from aircraft quality 4340 degassed material. Each rod is fully machined in the Manley Lakewood, NJ factory to the highest standards. Their signature “Turbo Tuff” design combines the appropriate weight and rugged strength for the ultimate horsepower applications. Each rod is shot peened after machining and magnaflux inspected. Bore are round and without taper. Bend and twist is tightly controlled. Cap fasteners are 3/8″ ARP 2000 cap screws.