A Performance-Friendly Sending Unit For 7.3L & 6.0L Power Strokes

Everyone wants the added performance and horsepower support that comes with an aftermarket lift pump system. The problem is that these high-flow, chassis-mounted fuel supply systems require you to either run a draw straw or a sump in the factory fuel tank. This leads to the dreaded “quarter-tank” issues that run rampant in the diesel industry. Run too low on fuel and you risk air being drawn into the system, which leads to super-heated fuel and even cavitation of the lift pump.

After noticing that ’99-’07 Ford owners had been left out in the cold with their 7.3L and 6.0L Power Strokes, Fleece Performance Engineering expanded its line of SureFlo Performance sending units to include them. Already offered for ’01-’16 Duramax and ’91-’24 Cummins owners, the company’s SureFlo product works by pulling fuel from (and returning fuel to) the bucket assembly at the base of the sending unit in order to ensure only fuel (and never air) is drawn into the fuel system.

Like every product Fleece develops, the quality of these sending units is second-to-none. The ’99-’07 Power Stroke market just got a huge shot in the arm with this simple, bolt-in improvement. Below, we’ll explore the SureFlo Performance sending unit in detail.

What’s In The Box

Within the packaging, Fleece includes every supporting piece required to bolt its SureFlo Performance sending unit onto your ’99-’07 Ford. Along with the SureFlo sending unit itself, you get a new tank flange square-cut O-ring (note that your tank’s original sending unit lock ring is reused), the required level send float, and a plug-and-play adapter harness. The supplied hardware includes (2) 90-degree -8AN to hose barb fittings, (2) -8AN to ¾-16 adapter fittings, one 90-degree -10AN to hose barb fitting, and a -10AN to ¾”-16 adapter fitting. The SureFlo Performance sending unit retails for $376.95.

Direct-Fit Replacement

It’s important to note that the Fleece SureFlo unit can serve as either a replacement sending unit for a 100-percent stock truck, or for one that’s equipped with an aftermarket low-pressure fuel supply system. It’s also worth pointing out that, while the SureFlo is nearly identical in appearance to Fleece’s popular PowerFlo in-tank lift pump, the SureFlo sending unit doesn’t contain a fuel pump. As you can see here, the SureFlo sending unit comes completely assembled, with support rods already pressed into it (as well as the spring-loaded ends pressed into the unit’s lift bucket base).

Brand-New Float Arm (And Fuel Level Electronics)

Prior to installation, the installer will have to attach the fuel level float arm. It is secured to the sending unit by carefully clipping the arm into the fuel level sensor. Later on, when dropping the sending unit into the fuel tank, special care should be taken so as not to bend or damage the fuel level float arm, or place unneeded stress on the resistor card element. Once the sending unit is in place in the tank, it’s also important to avoid rotating the assembly unnecessarily.

FASS, AirDog and OEM Compatibility

Each SureFlo is topped off with a CNC-machined, heavy-duty, billet-aluminum cap like this. The cap features an integrated auxiliary return port, which arrives with a plug installed. If you’re running a FASS low-pressure fuel supply system, the port will be utilized. However, if your truck is equipped with an AirDog system its use isn’t warranted. Used in conjunction with the OEM lift pump, the SureFlo’s installation is about as straightforward as it gets, with the supplied barb fittings seamlessly accommodating the factory fuel lines.

Proper Install Orientation

As for proper orientation of the SureFlo sending unit within the tank, it’s different between the two Power Stroke engine models. On 7.3L versions, the SureFlo’s billet cap should be positioned with its indentation mark lined up with the notch present in the tank flange (left). For 6.0L Power Stroke applications, the sending unit’s billet cap should be oriented so that the indentation mark lines up with the dot on the factory tank (right). Regardless of which model the SureFlo is installed in, it’s important not to over-tighten the OEM sending unit lock ring.

Written by Mike McGlothlin