#4 Str Fem to 1/8in NPT Swivel Adapter

The #4 Straight Female to 1/8in NPT Swivel Adapter (XRP 900604) is a critical fitting for custom fuel, oil, and coolant line systems in high-performance and modified vehicles. Built by XRP-XTREME RACING PROD., this adapter bridges AN-sized hose connections to NPT-threaded ports, making it indispensable for engine bay plumbing on race cars, turbocharged builds, and precision fuel delivery applications where standard connectors won't fit.

Machined from lightweight aluminum and anodized in blue and red for corrosion resistance and visual identification, this fitting features a swivel female end that accepts #4 AN hose (5/16" ID), while the 1/8 inch NPT male threaded side screws directly into engine blocks, fuel rails, or manifold bosses. The swivel design reduces installation stress on hard lines and hose assemblies, allowing a full range of motion without kinking or binding—critical when space is tight or vibration is intense. Precision tolerances ensure leak-free operation under pressure, a non-negotiable requirement in fuel and forced-induction systems.

Street and strip builders rely on this adapter when converting factory NPT ports or adapting aftermarket fuel systems, oil cooler lines, and catch-can drains. Its compact footprint (2.75 x 0.9 x 3.65 inches) fits confined engine compartments, and the anodized finish withstands fuel contact, heat cycles, and salt exposure. This is the adapter professionals stock for quick solutions when fabricating custom hydraulic or fluid circuits on turbocharged, supercharged, and LS-swapped vehicles.