(FORD SB 3/8 x 1.670" 12pt header stud kit - Black) ARP manufactures premium grade bolt kits to facilitate installation of exhaust headers in both stainless steel or 8740 chrome moly steel. The stainless 300 material is not affected by corrosion or extreme heat, making it ideal for the application. What's more, the compact 12-point nut version lets you easily slip a socket close to the pipe. Standard:Each ARP bolt kit includes the specific number of parts for your application, plus premium-quality washers and hex or 12-point nuts, as required. The black oxide finished chrome moly bolts and stainless steel fasteners are nominally rated at 170,000 psi tensile strength. Drilled:ARP offers special NASCAR header bolts that have been drilled for use of safety wire. They are made from heat-treated 8740 chrome moly steel (with a black oxide finish - rated at 180,000 psi) or Stainless 300 that is polished to a bright shine (nominally rated at 170,000 psi tensile strength - considerably stronger than Grade 8 hardware), and engineered to provide complete reliability in the most severe racing environments. They are available in hex or 12-point heads. Through use of safety wire, exhaust headers will maintain original tightness and can't back off!SB = Small BlockBB = Big Block