EVIL ENERGY 6AN Male to 5/16" Quick-Disconnect Fuel Rail Adapter — 2-Pack Aluminum, 1500 PSI

This kit contains two precision-machined 6061-T6 aluminum adapters designed for high-pressure fuel applications. Each adapter threads into a 6AN (9/16-18 UNF) port and accepts a 5/16" quick-disconnect female fuel line, with a 37° flare sealing surface to help prevent leaks. Rated for up to 1500 psi and a broad temperature range from -40°F to 250°F, these fittings suit common automotive use-cases like fuel rails, LS swaps, return lines and fuel sensors.

How do these adapters connect to my existing fuel system?

The adapters screw into standard 6AN (9/16-18 UNF) flare ports and receive a 5/16" quick-disconnect female line. The 37° flare provides the sealing interface while the internal bore matches 5/16" ID lines for smooth flow. Installation is straightforward with appropriate tools and thread seal precautions.

• Threads: 6AN (9/16-18 UNF) male
• Outlet: 5/16" quick-disconnect female inlet
• Sealing: 37° flare angle to reduce leak risk
• Includes two matching adapters for paired installations

Are these fittings strong enough for high-pressure EFI systems?

Yes — the fittings are CNC-machined from 6061-T6 aluminum, a material commonly used in automotive fluid fittings for its strength-to-weight ratio. With a working pressure rating of 1500 psi and a wide operating temperature window, they handle typical EFI, return, and sensor-line pressures encountered in performance and street applications.

• Material: aluminum alloy 6061-T6 for corrosion resistance and durability
• Working pressure: rated up to 1500 psi
• Temperature range: -40°F to 250°F for varied environments
• Precision flare sealing reduces chance of fuel seepage

What vehicles and setups commonly use this adapter?

These adapters are versatile for many gasoline and EFI configurations where a 6AN port must accept a 5/16" quick-disconnect line. Typical applications include aftermarket fuel rails, LS engine swaps, transmission cooler feed/return lines, and aftermarket fuel sensor installations. They’re also suitable when converting or adapting between hose sizes during custom plumbing work.

• Fuel rails and aftermarket EFI systems (including LS swaps)
• Fuel return lines and sensor plumbing
• Transmission cooler and other fluid lines with compatible fittings
• Custom plumbing projects needing 6AN to 5/16" conversion

What should I know before installing these adapters?

Prepare compatible threads, ensure correct torque, and inspect sealing surfaces before use. Use proper thread sealant if required for your application (avoid sealants that can contaminate fuel), and check manufacturer guidance for torque specs on aluminum fittings. Pressure-test the system after installation to confirm leak-free connections.

• Check port threads: 9/16-18 UNF (6AN standard)
• Inspect 37° flare for nicks or debris before assembly
• Use recommended torque and compatible thread sealant if needed
• Perform a pressure/leak test after installation

Who is this for? These EVIL ENERGY aluminum adapters are aimed at mechanics, tuners, and do-it-yourself automotive enthusiasts who need a reliable 6AN-to-5/16" quick-disconnect solution for fuel rails, LS swaps, return lines, and sensor plumbing. They’re ideal for anyone seeking lightweight, corrosion-resistant fittings rated for high-pressure EFI systems and short-run custom plumbing tasks.