EVIL ENERGY 6AN to 3/8-inch Hardline Compression Adapter Black 4-Pack — Aluminum Body with Brass Ferrule

EVIL ENERGY's 6AN male to 3/8" hardline compression adapter is an aluminum flare-to-hardline connector that converts a 6AN male (9/16-18 UNF) flare fitting to a 3/8" OD stainless or aluminum hardline using a brass ferrule seal.

This compact adapter lets you join AN-flared fuel or fluid lines to rigid 3/8" hard tubing where a compression-style connection is required. Machined from lightweight aluminum with a brass ferrule, the fitting uses a 37° flare angle on the AN side for sealing and is sold in a convenient 4-piece set. Before installation, confirm the hardline outside diameter and material — these adapters are designed specifically for 3/8" stainless steel or aluminum hardlines.

How does this adapter connect a 6AN line to a hardline?

The adapter threads onto a 6AN male flare (9/16-18 UNF) and compresses a brass ferrule around a 3/8" OD hardline, creating a mechanical seal. The AN side seals against the 37° flare face while the ferrule bites the tubing when the nut is tightened.

• 6AN male thread size: 9/16-18 UNF for standard AN flare fittings
• Hardline compatibility: accepts 3/8" outside-diameter stainless or aluminum tubing
• Sealing method: 37° flare on AN side plus compression ferrule on hardline side
• Sold quantity: four adapters per pack for multi-connection projects

Which materials and finishes are used, and why do they matter?

Each adapter body is aluminum alloy to reduce weight and resist corrosion, while the ferrule is brass to provide a durable, deformable gripping surface on metal tubing. The black finish helps resist surface wear and provides a discreet look in engine bays or custom fuel systems.

• Body: lightweight aluminum alloy for strength and low weight
• Ferrule: brass ferrule provides reliable compression on hardline
• Finish: black coating for added wear resistance and aesthetics
• Use-case durability: designed for automotive fuel delivery and general fluid systems

What should I check before buying and installing these adapters?

Measure the hardline outside diameter and verify the tubing material — these compression fittings are intended only for stainless steel or aluminum hardline, not for soft tubing like rubber. Also confirm you need a 6AN (9/16-18 UNF) flare interface; incorrect thread or tubing size will compromise the seal.

• Confirm hardline OD is 3/8" (measure with calipers if unsure)
• Verify tubing material: stainless steel or aluminum only
• Check mating AN fitting: 6AN male (9/16-18 UNF) flare required
• Inspect ferrule seating and torque per system guidelines during install

Who is this for? This 4-piece EVIL ENERGY adapter pack suits mechanics, fabricators, and DIY tuners who need to transition from AN-flare plumbing to rigid 3/8" hardline in fuel delivery, oil return, or custom fluid systems. It’s ideal for projects requiring a lightweight, corrosion-resistant connection where a compact compression-style fitting is preferred. If you work on performance engines, classic restorations, or custom plumbing runs and already use AN fittings, these adapters provide a straightforward, serviceable bridge to hard tubing — just confirm sizes and materials before installation.