EVIL ENERGY 6AN to 5/16" Quick-Disconnect Female Adapter Pair — 37° Flare, 6061-T6 Aluminium, 1500 PSI

EVIL ENERGY's 6AN male to 5/16" quick-disconnect female push-on fitting (2 pieces) converts a 6AN threaded line to a 5/16" spring-lock fuel hose with a sealed 37° flare for leak-resistant connections.

This pair of fittings bridges common aftermarket fuel and fluid plumbing standards, letting you join AN-style hard lines or adapters to OEM-style 5/16" spring-lock hoses quickly and reliably. Machined from 6061-T6 aluminum with a 37° flare sealing face and plastic spring-retainer, the fittings are built for high-pressure engine and transmission fluid work across a broad temperature range.

How does this fitting stop leaks on high-pressure lines?

The fitting uses a 37° flare sealing geometry that mates to the corresponding flare on the 6AN male side to provide a metal-to-metal seal. The female quick-disconnect side features a spring-lock design that snaps onto 5/16" hose assemblies for a secondary retention point. Together they minimize leak paths when installed correctly and torqued to proper spec.

• 37° flare sealing face prevents seepage at the AN connection.
• Spring-lock female accepts standard 5/16" push-on hose fittings.
• Machined aluminum body resists corrosion and maintains flange precision.

What operating conditions can these fittings handle?

These fittings are rated for working pressures up to 1500 psi and have a usable temperature range from -40°F to 176°F, making them suitable for many fuel, return, and cooler-line applications. The aluminum alloy body keeps strength at elevated temperatures while the plastic spring lock maintains secure retention in typical under-hood conditions.

• Working pressure: up to 1500 psi for fuel and fluid circuits.
• Temperature range: -40°F to 176°F for most automotive environments.
• 6061-T6 alloy retains dimensional stability under temperature cycling.

Which installations and systems is this adapter used for?

These adapters are designed for fuel rails, LS-swaps, transmission coolers, return lines, fuel sensors, and similar engine-bay plumbing where converting AN threads to 5/16" spring-lock hose is necessary. Their compact shape keeps routing simple in tight engine compartments and helps integrate aftermarket fittings with factory-style hoses.

• Fuel rails and EFI plumbing for aftermarket conversions.
• Return lines and fuel sensors that require 5/16" quick-disconnect hoses.
• Transmission cooler or fluid lines using a 6AN to 5/16" interface.

How should I install and maintain these fittings for best results?

Hand-start the 6AN thread, then tighten evenly to avoid cross-threading and ensure the 37° flare seats squarely. Push the spring-lock side fully onto the 5/16" hose until the retainer clicks; inspect for play and test under pressure before first use. Periodic visual inspection for wear, corrosion, and secure retention is recommended, especially after heavy vibration exposure.

• Start threads by hand and torque to manufacturer guidance for AN fittings.
• Ensure spring lock fully engages the 5/16" hose with audible click.
• Inspect seals and retainer after initial run-in and at service intervals.

Who is this for: Professional tuners, engine builders, and experienced DIYers converting or repairing fuel and fluid systems who need a compact, high-pressure adapter to join 6AN male lines with 5/16" spring-lock hose. If you work on LS swaps, EFI fuel rails, transmission cooling lines, or retrofit OE hoses to AN fittings, this 2-piece EVIL ENERGY adapter provides a durable, sealed option to simplify plumbing transitions.