Billet Cap & Neck Assy.

The Peterson Fluid billet cap and neck assembly (MPN 08-0611) is a precision engineered fluid containment component designed for high-performance cooling and fuel system applications. This weld-on bung kit serves as a secure access point for radiators, overflow tanks, and custom fluid reservoirs in racing, automotive, and industrial builds. The assembly combines a robust aluminum bung with a threaded aluminum cap, providing a dependable seal for systems operating under varying pressure and temperature conditions.

Built from lightweight aluminum construction, this billet cap and neck assembly features a 1.438-inch outer diameter designed for direct welding into tank walls or custom fabrication. The red anodized finish delivers both aesthetic appeal and corrosion resistance, protecting the assembly in harsh engine bay environments. The threaded cap mechanism ensures a tight, repeatable seal while allowing quick access for fluid checks, top-offs, or system maintenance. The compact 2.85 x 1.15 x 3.75-inch profile minimizes packaging interference in space-constrained engine compartments.

This kit is ideal for fabricators, race teams, and custom builders who require reliable OEM-quality tank access solutions without factory constraints. The weld-on design integrates seamlessly into aluminum or steel tanks during fabrication, making it a preferred choice for prototype development and one-off builds. Installation requires basic welding skills and compatible fuel or coolant systems—verify tank material compatibility and pressure rating before deployment. The lightweight construction (0.12 lbs) makes it an excellent choice for weight-conscious performance applications.