All Ford fuel injector systems from the mid 80's to the late 90's used a fuel reservoir for the high pressure fuel injection pump.

I would not think a gutted fuel filter would work as a fuel collector for the high pressure pump.
The glass bowl used on tractors gravity fuel system (no fuel pump) is used as a settlement collector so crap does not get into the carburetor.

 

Note also that the fuel reservoir also has check valve in it to keep fuel in the fuel lines so a one second run of the pumps will let the engine start. Without these check valves it would mean longer cranking time also. The single tank reservoir may or may not have a filter in it depending on the year of the truck.



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I checked 2 local yards yesterday and was unable to locate this reservoir - only the dual-function that I could find on the trucks. This got me thinking though, I still need a reservoir, but only in single function. I have not taken the dual function one apart, but I am curious if it is possible to modify it internally so that it can be used as a single without worrying about the flow accidentally being redirected out the other unused ports.

 

It works like this:


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I tore the DFR completely down to see how it works and it's just as you described. It seems silly for me to try to find a SFR if I plan on switching to the electrical selector. The valves are spring-loaded and as long as they aren't locked in the down position, the normal operating position is for them to flow through the top ports. In theory, all I should need to do is cap off the 2 bottom ports and I have the same functionality as the SFR.

 

Well before I could commit any reckless acts of poor James Bond engineering my wife told me she needed to pick up feed next week. I bought the SFR new from LMC for $79+ s&h. New in tank and hi volume pump are already done. I'm keeping the rear tank and losing the midship tank. Least this way if I ever wanted to put in true duals I won't have the side tank in the way. Thanks Subford for the advice, and Tristanlee I'll be watching how your experiment with converting the dual to a single. I still have the failed dual in the shop 😊

 

Here's the update for converting this back to using both tanks and switching to an electronic fuel selector rather than the stock diaphragm.

Not that it matters much about the fuel swap, but I wanted to show the truck that I am working on. This truck belonged to my grandpa that he purchased brand new after retiring. Many memories were made when my brother and I were young and we'd ride with grandpa out to go fishing on the farm. It's also the first vehicle my grandpa taught me to drive a manual. My grandpa passed away in Aug 2015 and the truck has been sitting for over 8 years. Now that it is in my possession and has sentimental value, I wanted to bring it back to life.



After dropping the tanks to remove the fuel, I noticed that the rear one was so rusted that it needed to be replaced with a new pump. Because I would have hated to get this all back together and have the front pump fail shortly after, I decided to buy 2 new tanks with new pumps, senders, new fuel line, inline filters, new high pressure pump and main filter.



I ditched the stock DFR to be replaced with a Pollak 6-port electronic selector. I ended up welding a small bracket to the frame to mount this right before the reservoir.




You can see the inline filters from each feed line from the tanks prior to the selector. The high-pressure pump and filter are new as well.


For wiring up the new selector valve, I originally looked at the write-up Kevin had that I linked previously. After studying his wiring diagram, I became more and more confused on how the best way to do this. It's not that his diagram is wrong because it certainly worked for him, but with the need for re-wiring the switch and wiring the senders and fuel pumps into the new selector, it seemed over-complicated. The truck from the factory does all of that, and does it pretty well already if your switch isn't bad and wiring hasn't been chewed up.

Instead, I decided to piggy-back off the existing switch and wiring with a DPTP relay. The selector valve works by operating the front tank when 12v is supplied to pin E and ground to pin D. To switch to the rear tank, the polarity just needs inverted. This is where the relay comes in:


I tapped into the stock harness for 2 references: I need a constant 12v in the key-on position after the inertia switch (middle red/yellow wire) and I need a 12v reference to energize the relay coil which will invert the voltage polarity to the selector to switch to using the rear tank lines. For that, whenever the switch is in the down (rear) position, the brown/white wire gets 12v to run the rear fuel pump, so I can use that to energize the relay coil to activate the selector valve for the rear lines:


The selector valve takes 5 wires: 2 sender references, 1 sender output to the gauge, and 2 for toggling to internal valve position. However, because I am still using the stock switch for powering the pumps and reading the senders, all I needed was to just run 2 wires to the selector valve to set its position. I brought them through the firewall in the black wire loom you see pictured here:


When it's all said and done, the wiring is clean and compact right under the switch, and the rest is handled under the truck: