https://www.bobsspeedometer.com/1/120/services.aspThese guys rebuild fuel gauge sending units.
Finding NOS will be difficult.
My 79 has a plastic tank, 32 gal.
And yes, I have an extra fuel filter cannister type right under cargo door area.
My pickup has a return that goes to charcoal canister if i remember correctly.
I had a high speed fuel starvation that was fixed by changing the canister fuel filter.
I also had incorrect fuel gauge readings that changing the sending unit did not fix. installed a solid state circuit board in dash and fuel gauge has been dead on since.
https://premiumdashdecals.com/ PDD118 fits Dodge oem board # 4075049
They also have another for 76 – 80 Dodge Vans B Series, Sportsman, Custom Circuit Board
https://premiumdashdecals.com/shop/...-b-vansportsmancustom-van-standard-dash/