7.89mm Quick Connect Fuel Fittings for 39mm Pumps | Single and Dual Options from OneFastShop

If you have ever upgraded a fuel pump and then fought with hose clamps, leaky barb fittings, or adapters that do not quite line up, you already know the pump swap itself is rarely the hard part. The connection back to your factory fuel line is where most builds get messy - and where most slow, maddening fuel leaks are born. OneFastShop makes two quick-connect fittings that solve this cleanly - a single-output version and a dual-output version - both built specifically for the Walbro 39/50 DCSS pump family (450, 525, 535).

Here is the problem they solve, how each one works, and which setup is right for your build.

The Problem They Solve

Here is the mismatch at the heart of nearly every aftermarket pump install: most aftermarket pumps use a barbed outlet, while your factory fuel line terminates in a quick-connect fitting, not a barb. The two do not speak the same language. So to bridge them, builders typically end up with an adapter, a length of fuel-rated hose, and a clamp or two - which means three or more extra connections, each one a potential leak point, and all of them buried inside the fuel tank where you cannot see or easily reach them. Hose clamps loosen with heat cycling and vibration, and standard rubber hose hardens, cracks, and degrades over time - a process that ethanol blends like E85 accelerate dramatically. In other words, the “quick” hose-and-clamp bridge is the part of the install most likely to come back and haunt you.

These fittings eliminate all of that. They mount directly to the pump outlet and give you a factory-style 7.89mm quick-connect port that clicks straight into your OEM fuel line. No clamps, no rubber hose in between, no permanent modifications - just a single, secure, factory-style connection where there used to be three fragile ones.

OneFastShop 7.89mm Single Outlet Fitting

The single outlet fitting is the right choice for most pump upgrades. If you are running a single pump with a standard fuel feed - which describes the large majority of Stage 2-style builds - this is all you need.

It is CNC-machined from 6061 aluminum with a black anodized finish, and it converts the pump outlet into a single 7.89mm SAE male quick-connect port. It slips over the pump outlet stub and is secured with a tightening collar, while an internal Viton O-ring creates the leak-free seal. Viton is the detail that matters most here: it is fully compatible with ethanol blends including E85, which swells and degrades standard rubber seals over time. Using the wrong O-ring material on an ethanol car is exactly how a connection that sealed fine on day one starts seeping months later. The fitting is also reusable, so if you swap pumps down the road it comes off and goes onto the next one rather than being thrown away.

OneFastShop 7.89mm Dual Outlet Fitting

The dual outlet fitting gives you two 7.89mm quick-connect ports, and the key thing to understand - which the spec sheet makes clear and most people miss - is that it works in two genuinely different configurations depending on how you plumb it:

• Single-pump splitter: one pump feeds both ports. This is useful for dual-feed lines, parallel fuel rails, or high-flow setups where you want to split flow from one pump into two paths.
• Dual-pump combiner: the fitting mounts on Pump A, Pump B’s output connects into one port, and both pumps’ flow combines and exits the remaining port to the car. This is the classic configuration for dual in-tank pump setups on high-power builds, where one fitting cleanly merges two pumps into a single feed line.

So the same part serves the builder splitting one pump and the builder combining two - it just depends which ports are inputs and which is the output. Like the single version, it is CNC-machined 6061 aluminum with a Viton O-ring, slip-on collar mounting, full E85 compatibility, and reusability.

Which One Do You Need?

For most builds, the single fitting is the right call - if you are upgrading to a Walbro 450, 525, or 535 with a standard single feed to your rail, it does the job cleanly and you do not need to overthink it. Choose the dual fitting if your build specifically needs two lines from one pump, or if you are running a dual in-tank pump setup and need to combine both pumps’ output into one feed to the car. If you are not running duals and do not have a dual-feed fuel system, the single is what you want.

Pump Compatibility

Both fittings are engineered exclusively for the Walbro / TI Automotive 39/50 DCSS pump family, which share the same outlet stub design:

• Walbro 450 LPH (F90000267 / TIA485-2)
• Walbro 450 LPH High Pressure (F90000274 / TIA450-2)
• Walbro 525 Hellcat (F90000285 / TCD470)
• Walbro 535 Hellcat Plus (F90000295 / TCD495)

They do not fit Walbro 255/350 LPH (GSS-series), AEM, DeatschWerks (including the DW400/DW440), Aeromotive, or any inline pump - those use different outlet designs. Confirm your pump matches one of the part numbers above before ordering, since the fit is specific to this pump family’s outlet stub.

Why the Connection Matters

It is worth restating, because it is the whole point: a loose clamp or a degraded section of hose inside your fuel tank is genuinely awful to diagnose and awful to fix - it means dropping the tank again to chase a leak or a pressure problem you cannot see. These fittings take one of the most common weak points in an aftermarket fuel pump install and turn it into one of the most secure, factory-grade connections in the entire system. On a job you would much rather do once, that reliability is the real value. Both are in stock and ready to ship.

Get the single outlet fitting here, or the dual outlet fitting here.

Frequently Asked Questions

What pumps do these 7.89mm fittings fit?

They fit the Walbro / TI Automotive 39/50 DCSS pump family only: the 450 (F90000267 and F90000274), 525 Hellcat (F90000285), and 535 Hellcat Plus (F90000295). They do not fit GSS-series Walbro, AEM, DeatschWerks, Aeromotive, or inline pumps.

What is the difference between the single and dual fitting?

The single fitting gives one 7.89mm quick-connect output for a standard single-pump feed. The dual fitting gives two ports and can either split one pump into two lines or combine two pumps into a single feed for dual in-tank setups.

Why are factory-style quick-connect fittings better than hose and clamps?

A hose-and-clamp bridge adds multiple connections inside the tank, and clamps loosen while rubber hose degrades over time, especially on E85. A direct quick-connect fitting removes those extra joints and gives you a single secure, factory-style connection that is far less likely to leak.

Do I need hose clamps or adapters with these?

No. The fitting mounts directly to the pump outlet with a tightening collar and provides a factory-style 7.89mm quick-connect that clicks into your OEM fuel line. No clamps, hose, or permanent modifications.

Are these fittings E85 compatible?

Yes. Both use an internal Viton O-ring that seals against gasoline, ethanol blends including E85, methanol, and race fuels - Viton resists the swelling and degradation that ethanol causes in standard rubber.

Can I reuse the fitting if I swap pumps?

Yes. Both fittings are reusable and support multiple installations, so they transfer to your next pump as long as it is in the supported Walbro family.