Wedge Locking Header Bolts - 3/8 x 3/4L (12)

PROFORM Wedge Locking Header Bolts in 3/8 x 3/4L configuration deliver precision fastening for high-performance engine assembly and racing applications. This 12-piece set features 3/8-16 thread specification with 0.75-inch length, hex head design, and black oxide finish—standard fare for serious engine builders and performance shops working on small-block and mid-sized platforms. The wedge lock mechanism prevents bolt rotation and maintains clamp load under vibration, critical when assembling cylinder heads where thread security directly impacts reliability.

Each bolt measures 3/8-inch diameter with a 16-threads-per-inch pitch and 0.75-inch overall length—dimensions engineered to fit standard header flange applications without interference. The black oxide coating provides corrosion resistance in engine bay environments, protecting against moisture and heat cycling that would degrade bare steel. Hex head geometry allows socket or wrench engagement without slipping, essential when torquing to specification during engine assembly. The wedge lock washer design creates a mechanical lock that resists loosening from thermal expansion, pressure pulsation, and vibration—eliminating the need for secondary locking methods on this critical fastener interface.

Engine builders, machine shops, and performance enthusiasts who assemble headers and cylinder head packages depend on wedge lock bolts to maintain torque and prevent catastrophic leaks. Racing applications—whether circle track, drag strip, or road course—subject headers to extreme thermal cycling and vibration. Stock fasteners frequently back out under these conditions; wedge lock designs address this wear-out problem directly. The 12-count set covers most small-block applications, reducing the need to source fasteners from multiple vendors.