For demanding race engine builds using IE Connecting Rods with standard ARP 2000 alloy 5/16", this rod bolt upgrade uses ARP's specialty formulated Custom Age 625 Plus.
This is for one upgraded rod bolt to replace the standard ARP 2000 alloy bolts shipped with all 5/16" IE Connecting Rods. For serious power builds, ARP's 625 Plus super-alloy demonstrates superior fatigue cycle life, tensile strength, and complete resistance to corrosion and oxidation. ARP was the first manufacturer to develop and test the difficult manufacturing process for 625+ alloy for rod bolt use. The result is well worth the effort offering a new level of rod bolt reliability in extreme engine applications for less cost than lesser improved alloys. Push your performance VW or Audi engine with IE Connecting Rods to the limits with ARP Custom Age 625+ alloy upgrade 5/16" rod bolts!
If you are upgrading your existing rods from ARP 2000 alloy bolts to 625+ Super-Alloy, the rods must be re-honed by a machine shop before installation due to the increased clamping force and higher torque spec. IE recommends buying your connecting rods with +625 bolts already installed with the proper machine work finished in-house beforehand.