AN Plug -4

The AN Plug -4 from Allstar Performance is a precision hydraulic and fuel system fitting engineered for high-performance automotive applications where reliable leak-free connections are non-negotiable. Designed for builders and technicians who demand OEM-quality components, this aluminum plug delivers the dependable sealing integrity required in racing engines, custom fuel systems, and pressurized fluid circuits. Whether you're assembling a competition engine or upgrading a street performance build, the AN Plug -4 ensures compatibility with industry-standard -4 AN (5/16-24) thread specifications.

Constructed from lightweight aluminum and finished in black anodized coating, this hex-head plug combines strength with corrosion resistance essential for fuel, coolant, and oil circuit applications. The hex head design allows secure installation and removal using standard wrenches, while the -4 AN port size (5/16 inch diameter) matches common performance fuel line, carbureted fuel systems, and cooling passages found in modern high-performance builds. Black anodized finish protects against oxidation and provides a professional appearance while maintaining structural integrity under temperature fluctuations and pressure cycles typical in racing environments.

Professional engine builders, fabricators, and motorsports enthusiasts rely on the AN Plug -4 to cap off unused ports in fuel manifolds, radiator housings, and custom-fabricated aluminum blocks and heads. Installation is straightforward: thread the plug into the -4 AN port and tighten using a wrench fitted to the hex head until hand-tight plus a quarter turn to ensure a secure seal without over-torquing. This fitting integrates seamlessly with any system using AN hose, adapters, and line components, making it essential inventory for dedicated performance shops and serious DIY builds.