Straight Adapter Fitting ; Size: -4 AN x 3/8in NP

The Vibrant Performance Straight Adapter Fitting in -4 AN x 3/8in NP is a precision hydraulic connector designed to bridge AN (Army-Navy) and NPT (National Pipe Taper) fluid line standards in high-performance automotive and industrial applications. This adapter serves as a critical interface component for fuel systems, coolant lines, and custom fluid routing where different port thread types must be reliably connected without leakage or system compromise.

Constructed from black anodized aluminum, this straight adapter fitting delivers both corrosion resistance and lightweight durability essential for engine bays and underbody installations exposed to moisture and thermal cycling. The -4 AN male port accepts standard four-size AN hose ends, while the 3/8-inch NPT male thread engages directly into factory or aftermarket manifold ports, eliminating the need for multiple fittings or adapters in series. Anodized aluminum resists oxidation while maintaining excellent machinability, ensuring a precise seal with proper torque application and compatible thread sealant.

This adapter is ideal for fuel injection conversions, turbo coolant systems, and custom plumbing where OEM ports use NPT threads but performance hoses employ AN fittings for quick-disconnect capability. Installation requires hand-tight seating plus 1–1.5 turns with a wrench; avoid over-torquing, which can crack the aluminum body. Compatible with any -4 AN hose assembly and any 3/8-inch NPT port on engines, transmissions, or auxiliary components, making it indispensable for serious enthusiasts and professional builders who demand leak-free, code-compliant fluid routing.