36 Piece Header Bolt Kit 3/8-16 x 1 Black Grade 8 Steel Bolts with Washers, 304 Stainless Collector Flange Bolts and Nuts, Compact 5/16 Hex Flange, Black Phosphate Coated, Fits Small Block Chevy SBC

This 36-piece header hardware kit is designed to provide a complete fastening solution for Small Block Chevy exhaust installations, combining high-strength header bolts, matching washers, and corrosion-resistant collector hardware in one package. Unlike standard bolt-only kits, this set ensures all critical connection points are properly equipped for installation. The header hardware includes 12 bolts and 12 washers manufactured from heat-treated 42CrMo alloy steel and built to Grade 8 specifications. This combination delivers reliable clamping force under high heat and vibration while allowing proper load distribution across the header flange for improved gasket sealing. Each bolt features a compact 5/16 inch hex head design, allowing improved access in tight header clearance areas where larger bolt heads can interfere with tubes or restrict tool movement. This makes installation easier in confined engine bays and on block hugger-style headers. The header bolts and washers are finished in a corrosion-resistant black phosphate and blackened coating tested to ASTM B117 standards. This finish helps protect against rust while maintaining a clean, low-profile appearance in the engine bay. The included collector hardware consists of 6 bolts and 6 nuts constructed from 304 stainless steel. This provides corrosion resistance and durability at the collector connection point, where exposure to heat, moisture, and road conditions is most severe. For proper installation, torque header bolts to 25–30 ft-lbs using anti-seize lubricant. Recheck after the initial heat cycle and periodically thereafter to maintain proper clamping force. Consistent torque retention is critical for long-term exhaust sealing. This kit is designed for Small Block Chevy engines including 265, 283, 302, 305, 307, 327, 350, and 400, which typically use 12 header bolts. Ideal for muscle cars, restorations, street rods, and performance builds, this 36-piece set provides a complete and reliable exhaust hardware solution.

• COMPLETE 36 PIECE HARDWARE SET – Includes 12 header bolts, 12 matching washers, plus 6 collector bolts and 6 collector nuts for a complete exhaust installation solution from header flange to collector connection.
• GRADE 8 HEADER BOLTS AND WASHERS – Header bolts and washers are manufactured from heat-treated 42CrMo alloy steel and built to Grade 8 specifications for reliable clamping under high heat and vibration.
• COMPACT 5/16 HEX HEAD DESIGN – Smaller hex head allows improved access in tight header clearance areas where standard bolts are difficult to install. Ideal for block hugger headers and confined engine bays.
• BLACK PHOSPHATE COATED HARDWARE – Header bolts and washers feature a corrosion-resistant black phosphate and blackened coating tested to ASTM B117 standards for durability and a clean engine bay appearance.
• 304 STAINLESS COLLECTOR HARDWARE – Collector bolts and nuts are constructed from 304 stainless steel for corrosion resistance and long-term durability at the exhaust collector connection point.