EVIL ENERGY 6AN Male to 5/16" Hardline Compression Adapter — 2-Pack, Aluminum Body with Brass Ferrule

EVIL ENERGY 6AN male to 5/16" hardline compression adapter converts a 6AN flare connection to a 5/16" hardline quickly and securely — sold as a pair.

Need a compact, durable adapter to join AN-style fittings with 5/16" hard fuel or fluid tubing? This two-piece set from EVIL ENERGY pairs an aluminum-alloy 6AN male flare body with a brass ferrule to clamp 5/16" stainless or aluminum hardline. The parts use the standard 37° AN sealing face and a 9/16" UNF thread on the 6AN male, delivering a reliable mechanical and pressure-resistant joint for automotive fuel, oil, or custom fluid routing projects. Measure your tubing OD before installing to ensure compatibility.

How does this adapter connect a 6AN line to 5/16" hardline?

The adapter uses a threaded 6AN male flare interface paired with a compression ferrule designed for 5/16" outer-diameter hard tubing. When tightened, the ferrule compresses onto the hardline while the 6AN flare seals against a 37° mating surface, creating a leak-resistant junction without solder or welding.

• 6AN male thread: 9/16" UNF, compatible with standard AN female flares.
• Compression ferrule fits 5/16" OD stainless or aluminum tubing.
• 37° flare angle on the AN face for mechanical sealing.
• Sold as a pack of two for tandem installations or spares.

What materials and construction should I expect?

The body of each adapter is machined from aluminum alloy for light weight and corrosion resistance, while the ferrule is brass to give a durable, deformable surface that grips hardline without cracking. This combination balances strength, corrosion performance, and ease of installation for automotive environments.

• Aluminum-alloy adapter body resists oxidation and keeps weight down.
• Brass ferrule deforms predictably for a tight compression seal.
• Precision machining ensures thread and sealing-face accuracy.

Which systems and tubing types can use this fitting?

These adapters are intended for fuel delivery, oil return, and other fluid systems where AN fittings and hardline meet. They are compatible only with 5/16" OD hard tubing made from stainless steel or aluminum — soft or polymer tubing is not suitable for compression-type ferrules.

• Common uses: fuel lines, fuel rails, return lines, turbo plumbing adapters.
• Compatible tubing: 5/16" OD stainless steel or aluminum hardline only.
• Not designed for soft rubber, nylon, or braided hose without proper inserts.

How should I prepare and install the adapter safely?

Proper prep and tightening are important for a lasting seal. Cut and deburr the hardline squarely, slide the brass ferrule onto the tubing, then thread and hand-start the 6AN male into its mating female. Tighten to manufacturer-recommended torque or until the ferrule compresses; do not overtighten, which can damage the ferrule or tubing.

• Cut tubing square and remove burrs for uniform compression.
• Verify tubing OD = 5/16" before assembly.
• Tighten gradually, checking for proper ferrule compression and no leaks.

Who is this for? This EVIL ENERGY adapter pair is aimed at mechanics, fabricators, and DIY car enthusiasts who need to transition between AN flare fittings and 5/16" hardline in fuel or fluid systems. If you work on engine swaps, custom fuel rails, or detailed plumbing where compact, reliable hardline connections are required, these adapters offer a lightweight, serviceable solution. Confirm tubing material and outer diameter before ordering to ensure fitment.