I have a 1991 E-350 club wagon XL Van. I am looking at removing the 22 gallon tank and installing a larger one. I have seen on other threads of using a Bronco 33 gallon tank, (TNKF8D) this tank will fit in the same place as the OEM tank, it will be 4-1/2" lower. I know I have to modify the tank straps for the new depth. I don't think this will be a huge concern.

My question is: Will the existing dash fuel gauge read correctly with the deeper tank? Do I need different pick up tube and fuel gauge sender unit? what do I need to have an accurate dash gauge?

 

Because the float can go down further with the larger tank, it will provide a different resistance and therefore different reading. the sending unit presently in the replacement tank should work with the present dash unit.

 

Good information, Should I get a sending unit with a longer float arm, if one is available, or adjust the existing float, if possible? If the dash gauge is not accurate. I will have to calculate miles per tank to determine when to fill up. That may be a problem when I am not the driver. Does anyone know of a 1991 Ford 3-5/8" sending unit with a longer float arm that will has the same wire connection/?

 

I would think the length of the float arm is what is critical due to the arc it travels.

What you might do is,
Compare the float arm lengths from each tank's sending unit and hopefully that will answer your concern.

 

Thanks, I plan on pulling the factory tank in the next week or so. I can check out the factory sending unit. I have no purchased the 33 gallon tank, or a sending unit yet. I am hoping to modify the factory sending unit. fingers crossed.