Straight Adapter Fitting #3 x 1/4 MPT

The Straight Adapter Fitting #3 x 1/4 MPT from FRAGOLA is a precision hydraulic and fuel system connector designed for custom automotive builds, fuel injection conversions, and high-performance engine modifications. This adapter bridges different port sizes and thread standards, allowing you to integrate new fuel rails, brake lines, or cooling system components into existing manifolds or block bosses without costly fabrication. Whether you're retrofitting a carbureted engine to EFI, upgrading brake hydraulics, or plumbing a custom fuel system, this fitting delivers the leak-free connection required for safety-critical applications.

FRAGOLA fittings are engineered from aerospace-grade aluminum and stainless steel, offering corrosion resistance and lightweight design essential in modern engine bays. The straight configuration eliminates the elbow offset, reducing pressure losses and simplifying routing in compact installations. The #3 (3/8") inlet threads directly into your component, while the 1/4" MPT (male pipe thread) outlet connects to standard -4 AN hose or adapter networks. The compact 4.05-inch length and 0.02-pound weight make this fitting ideal for tight spaces typical in engine bay modifications, transmission cooler lines, and fuel pressure regulator setups.

Experienced mechanics and engine builders favor FRAGOLA adapters for their reliability under sustained pressure and thermal cycling—critical when running modern fuel systems at 40–60 PSI or high-temperature coolant loops. This fitting is compatible with any fuel rail, brake proportioning valve, or manifold port using #3 JIC or NPT connections, making it a versatile solution for street rods, restorations, and track-focused builds. Installation requires basic metric wrenches and thread-seal tape or pipe dope; use the correct torque specifications for your application to ensure permanent, vibration-proof seals.