6AN vs 8AN vs 10AN: AN Fitting Sizing for Fuel Systems
By DeatschWerks | Published: 2026-11-05
Category: Kaufberatung
Use 6AN for stock-power feed lines, 8AN for mild builds, and 10AN for high-flow pumps. Here is how to size AN fittings, ORB adapters, and hose ends.
Quick answer
Match the AN size to your fuel pump outlet and power target: 6AN suits stock to mild setups, 8AN covers most street builds, and 10AN is for high-flow pumps and big power. Use ORB adapters only where the port thread matches, and step down with a coupler rather than forcing a mismatched hose end.
Why the pump outlet sets your AN size
AN sizes describe the hose and fitting bore, not the engine's power rating. A 6AN line can support more flow than a stock pump delivers, but a 10AN line on a low-output pump adds cost and weight without a benefit. Start with the pump outlet and work outward: if the pump discharges 6AN, a 6AN feed line keeps the system consistent. If the pump has a 10AN outlet, sizing down immediately creates a restriction you will fight later.
Where ORB adapters change the decision
ORB (O-ring boss) ports appear on many fuel pumps, regulators, and filters. An ORB adapter converts that port to a male AN flare, but the ORB thread size and the AN size are separate choices. A 6AN ORB to 6AN ORB adapter connects two ORB male threads with a swivel, which helps when you need to clock a fitting without twisting the hose. Confirm the port thread before ordering; the product listing does not supply a thread size, so measure or check the component documentation.
Straight vs 90-degree hose ends
A 90-degree hose end solves clearance problems near firewalls, frame rails, and tight intake paths. The trade-off is a tighter bend radius and more careful hose routing. For PTFE hose, a 90-degree swivel end with an olive insert is a common choice because the insert supports the hose liner. If your routing allows a gentle bend, a straight end is simpler and usually less expensive. Decide the angle after the hose path is mocked up, not before.
Couplers and step-downs
An 8AN to 8AN coupler joins two 8AN male flares, which is useful for extending a line or joining two hose assemblies. It does not change size; if you need to move from 8AN to 6AN, use a dedicated step-down adapter rather than a coupler. Keep couplers to a minimum because each joint is a potential leak point. When you do use one, confirm both ends are the same AN size and flare type.
Decision rules for sizing AN fuel fittings
- Start at the pump outlet: Measure or look up the pump outlet thread. If it is 6AN, run 6AN feed; if it is 8AN or 10AN, do not step down at the outlet unless a restrictor is required by the manufacturer. Write down the outlet size before buying any hose end.
- Choose ORB adapters by port thread, not AN size alone: An ORB adapter must match the port's thread size. The AN side is the hose size. If the port thread is not documented, measure it or contact the component maker; do not guess. A 6AN ORB adapter does not fit every 6AN port.
- Use a coupler only for same-size joints: An 8AN to 8AN coupler joins two 8AN male flares. For a size change, use a step-down adapter. Count couplers as extra leak points and keep them accessible. If you need 8AN to 6AN, a coupler is the wrong part.
- Pick the hose end angle after routing: Mock up the hose path first. Use a 90-degree end where a straight end would kink or contact a component. For PTFE hose, confirm the end includes the required olive insert. Buy the angle last, once the path is fixed.
Products that fit these decisions
- 6AN ORB to 6AN ORB Adapter: 6AN ORB male to 6AN ORB male swivel adapter with anodized DW Titanium finish. Lets you connect two 6AN ORB ports while allowing the fitting to swivel into position.
6AN ORB to 6AN ORB Adapter - 90-Deg. 10AN Swivel PTFE Hose End: 10AN female swivel hose end with a 90-degree bend, PTFE design, and one olive insert. Handles tight routing on 10AN PTFE hose where a straight end will not clear.
90-Deg. 10AN Swivel PTFE Hose End - 8AN to 8AN Coupler: 8AN male flare to 8AN male flare coupler in anodized DW Titanium. Joins two 8AN lines without changing size, useful for extending a feed or return run.
Who should choose which size
Best for
- Stock to mild street builds staying with a 6AN feed line
- Mild to moderate builds using 8AN feed and return lines
- High-flow pump setups and big-power builds needing 10AN feed lines
Not for
- Stock pumps that would see no benefit from 10AN lines
- Builds where the port thread is unknown and cannot be measured
- Situations where a coupler is being used to change AN size
