#4 to 1/8 NPT Str Gauge Adapter

The #4 to 1/8 NPT Str Gauge Adapter from XRP-Xtreme Racing Products is a precision fitting designed for high-performance automotive fuel and fluid system installations. This adapter bridges the gap between AN #4 port sizing and standard 1/8 NPT threaded gauge ports, making it essential for custom engine builds, fuel pressure monitoring setups, and aftermarket fuel system conversions. Whether you're installing a mechanical fuel pressure gauge on a carbureted engine or integrating electronic sensors into a fuel rail assembly, this adapter provides the critical interface needed to ensure accurate readings and reliable system operation.

Manufactured by XRP-Xtreme Racing Products, a trusted name in high-flow fuel system components, this straight adapter is precision-machined to exact specifications for leak-free performance under pressure. The #4 AN (Army-Navy) port accommodates standard braided stainless steel fuel lines, while the 1/8 NPT (National Pipe Thread) side accepts common gauge fittings and sensor ports found on most racing fuel pressure gauges and electronic fuel pressure transducers. The compact 2.75-inch body and lightweight construction (0.05 lbs) make installation straightforward in tight engine bay configurations, and the straight design minimizes turbulence and pressure drop compared to 90-degree alternatives—critical when tuning precise fuel delivery for carburetors or port-injection systems.

Street and strip builders routinely specify this adapter when upgrading fuel systems on vintage muscle cars, modern high-horsepower platforms, and fuel-injected conversions. It's indispensable for plumbing fuel pressure test ports, integrating aftermarket fuel pressure regulators, or tapping into custom fuel rails for real-time gauge monitoring. This adapter is compatible with any fuel system using #4 AN hose sizing and 1/8 NPT gauge or sensor ports—standard across Holley, Edelbrock, and most racing fuel system suppliers. Installation requires only basic fuel system knowledge and a pair of wrenches; simply connect your braided fuel line to the AN side and thread your gauge fitting or sensor into the NPT side for immediate operation.