16 Piece Header Bolt Kit 3/8"-16 x 1 Black Grade 8, 5/16 Bolt Head, Black Phosphate Corrosion Resistant Kit fits BBC Chevy, SBF Ford 289 302 351W & Moapr V8

This 16-piece header bolt set is designed for applications requiring full 16-bolt coverage, including big block and multi-platform V8 engines where proper clamping and fitment are critical. Manufactured from heat-treated 42CrMo alloy steel and built to Grade 8 specifications, these bolts deliver dependable strength for high-heat, high-vibration exhaust systems. The compact 5/16 inch hex head design provides a significant advantage during installation, allowing access in tight header clearance areas where larger bolt heads can interfere with tubes or restrict tool movement. This is especially beneficial on big block applications and engine bays with limited working space. Each bolt features an integrated flange design that eliminates the need for separate washers while evenly distributing clamping load across the header flange. This improves gasket sealing and reduces the risk of leaks by maintaining consistent clamping pressure. The black phosphate and blackened coating, tested to ASTM B117 corrosion standards, provides resistance to rust and corrosion while maintaining a clean, low-profile appearance in the engine bay. The finish is built to handle repeated heat cycles and real-world driving conditions. For proper installation, torque to 25–30 ft-lbs using anti-seize lubricant. Recheck after the initial heat cycle and periodically thereafter to maintain proper sealing. Consistent torque retention is critical for long-term header performance. This 16-piece kit is intended for engines requiring 16 header bolts, including Big Block Chevy 396, 402, 427, and 454, Ford small block and FE series engines such as 260, 289, 302, 351W, 351C, 390, and 428, as well as Moapr B and RB series engines including 383, 400, 413, 426, and 440. Small block Chevy applications typically use 12 bolts and should use the corresponding 12-piece kit. Ideal for muscle cars, restorations, street rods, and performance builds, this header bolt set delivers the strength, fitment, and installation access required for a reliable exhaust seal.

• GRADE 8 STEEL STRENGTH – Manufactured from heat-treated 42CrMo alloy steel and built to Grade 8 specifications for reliable clamping under high heat and vibration. Designed for performance exhaust systems and demanding installs.
• COMPACT 5/16 HEX HEAD – Smaller hex head design allows improved access in tight header clearance areas where standard bolts are difficult to reach. Ideal for big block applications and tight engine bay configurations.
• INTEGRATED FLANGE DESIGN – Built-in flange distributes load evenly across the header flange, eliminating the need for separate washers while improving sealing and simplifying installation.
• BLACK PHOSPHATE COATING – Corrosion-resistant black phosphate and blackened finish tested to ASTM B117 standards helps resist rust while maintaining a clean, low-profile engine bay appearance.
• PROPER TORQUE RETENTION – Designed to maintain clamping force through repeated heat cycles. Recommended torque is 25–30 ft-lbs with anti-seize. Recheck after initial heat cycle and periodically for best results.