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

EVIL ENERGY's 6AN female flare to 5/16" compression hardline fitting is a two-piece adapter that converts a 6AN 37° flare connection to a 5/16" OD hardline using a brass ferrule for a secure, metal-to-metal seal.

This compact adapter lets you join braided AN lines or male 6AN fittings to rigid 5/16" stainless steel or aluminum hardline without squeezing or modifying the tube end. Crafted from aluminum alloy with a brass ferrule, the fitting uses a 37° flare seat on the AN side and a compression-style ferrule on the hardline side, making it ideal for fuel delivery, brake lines, or custom engine plumbing where a reliable transition between flexible hose and rigid tube is needed. Confirm your hardline outer diameter and that the tube is suitable for compression-style fittings before installing.

How does this fitting create a leak-resistant connection?

The 6AN female side seals against a 37° flare on the male AN fitting, which is the standard sealing geometry for AN hardware. The hardline side relies on a brass ferrule that deforms slightly to bite the tube and form a mechanical compression seal. Together these two sealing methods provide a dependable junction when installed correctly.

• 6AN flange: 37° flare sealing surface for metal-to-metal contact
• Brass ferrule: compresses onto 5/16" OD hardline for mechanical grip
• Aluminium alloy body: resists corrosion and keeps weight low
• Thread size: 9/16-18 UNF on the 6AN female side

Will this fit my tubing and fuel components?

Use this adapter only when your rigid tube measures 5/16" outer diameter and is made of stainless steel or aluminum. The AN side matches any standard 6AN male (9/16-18 UNF) flare fitting. It is not suitable for soft copper tubing or unidentified plastic lines.

• Hardline compatibility: 5/16" OD stainless or aluminum tube
• AN compatibility: standard 6AN male with 9/16-18 UNF thread
• Not for use with soft-metal tubing like copper or with nonmetallic lines
• Measure tube OD before ordering to ensure proper fit

How should I install the compression-to-AN adapter?

Prepare the hardline with a square, burr-free cut and slide the brass ferrule onto the tube. Thread the fitting onto the male 6AN by hand, then tighten to recommended torque using appropriate wrenches—do not overtighten or use sealants on the flare face. After assembly, inspect for leaks under pressure before returning to service.

• Cut tube square and deburr to ensure ferrule seating
• Slide ferrule onto tube, insert into fitting fully
• Hand-start threads, then tighten with wrenches to proper torque
• Pressure-check the connection for leaks before final use

What materials and environments is this part suitable for?

The body is aluminum alloy and the ferrule is brass—materials chosen for light weight and resistance to corrosion in fuel and fluid systems. The fitting is commonly used in automotive fuel delivery, engine bay plumbing, and other mechanical systems, but it should be kept away from incompatible chemicals and extreme temperatures beyond typical engine compartments.

• Body: lightweight aluminium alloy for reduced weight
• Ferrule: brass for reliable compression gripping
• Applications: fuel systems, engine modifications, custom plumbing
• Limitations: not rated for nonmetal tubing or unknown aggressive chemicals

Who is this for: This 2-piece EVIL ENERGY adapter is aimed at DIY mechanics, performance tuners, and professional fabricators who need a compact, dependable transition from flexible 6AN systems to rigid 5/16" hardline. If you work on fuel delivery, turbo plumbing, or custom engine lines and need a lightweight, corrosion-resistant solution, this fitting provides a straightforward, serviceable option—just verify tube OD and material before ordering.