Chev LS1 5.7L Gen 111 ARP Harmonic Balancer Bolt Kit # 234-2503Chev LS1 5. 7L Gen 111 ARP Harmonic Balancer Bolt Kit # 234 2503 Harmonic Balancer Bolt, Chromoly, Black Oxide, 12 Point, All Gen. 3 4 Chevy, 4. 8, 5. 3, 6. 0L, 6. 2L, 7. 0L LS1, LS6, Each Thread Size: 16mm x 2. 0 Underhead Length (in): 4. 325 in. Head Style: 12 point Washer Included: Yes Fastener Tensile Strength (psi): 200,000 psi Fastener Material: 8740 chromoly Fastener Finish: Black oxide Quantity: Sold individually.