Ford 351 Cleveland ARP Chromoly Intake Manifold Bolt Kit # 154-2104Ford 351 Cleveland ARP Chromoly Intake Manifold Bolt Kit # 154 2104 Intake Manifold Bolt Kit, Black Oxide 12 Point, Ford 351C, 351M, 400, Kit Thread Size: 3 8 16 in. Washer Included: Yes Head Style: 12 point Fastener Style: Bolt Fastener Finish: Black oxide Fastener Material: Chromoly Quantity: Sold as a kit. ARP rugged, black oxide coated chromoly intake manifold bolts are rated at 170,000 psi. They're precision machined for optimum thread engagement