Fuel Sending Units-Are they interchangeable between tanks?

[mrtleavitt]

I was thinking about the in-cab gas tanks on the 67-72 Fords and I realize they come with a few different specs. I guess the EVAP ones are 18.5, the more common ones are 19.5 and I've been told a 21 gallon tank exists as well. I know the sending units will all work just fine in the different tanks, but are the sending units different to compensate for the larger or smaller tanks? Let me try to make this clearer, does a sending unit from a 21 gal tank have more travel than a sending unit from a 18.5 gal tank? I imagine they are all exactly the same and the difference is made up of how far the needle goes on the gauge, but I wanted to know if someone actually knows how this works.

[BiggDogg]

The float arms are typically adjustable, so the sending units should be the same for all the tanks... you may just need to adjust the float arm. I believe you would only need a different sending unit if you were changing your gauges to an aftermarket style.

[mrtleavitt]

So does adjustable mean that I just need to bend the float arm itself, or will there be some kind of a set screw on the unit?

[BiggDogg]

So does adjustable mean that I just need to bend the float arm itself, or will there be some kind of a set screw on the unit?

Its adjustable with a screw, but I found that when I replaced my float arm, the new arm was too long and not able to fully extend, giving me false readings on the gauge, so a little tinkering to find the right position, a quick cut on the arm, and we're good to go. Definately play with the screw adjustment first... maybe you'll get lucky and that will be all you need to do.

[westernkansas]

so how would a person know when they get it right on the money? If a person would buy one brand new would there be any adjust,ment needing made?