I have a 1966 econoline supervan with a bad sending unit, and I can't find one specifically for my year and model. So if there are any other vehicles I can search for that have the same unit, any help would be great.
By "sending unit" do you mean the sensor in the gas tank? If so, they are bad about grounding, so your sending unit may be fine.
Drill a small hole in the flange in the corner of the tank. (not where gas will leak out)
and drill a hole in the van frame. Put a sheet metal screw in each hole and run a wire between the two, and see if that helps.