85/86 CFI 5.0 Fuel Sending Unit

Like many others, my 85 GT AOD/CFI fuel gauge doesn't work. I found this one at Mustangsunlimited.com.
1 F4003R 01 FUEL SENDING UNIT 83/86 3.8/5.0L CFI 54.95

My son and I pulled the tank this morning and discovered that the part above was not right. It is much longer than the stock unit and is designed to work with a mechanical fuel pump. I pulled the existing unit, opened up the switch and sure enough the contacts were worn down to the circuit board. Apparently the 85/86 has a much shorter unit similar to an 87 thunderbird. This is a discontinued item everywhere I looked, but I think I found one. I'll report back when I get the part to see if it's right. This stock unit is supposed to have 8-12 ohms full and 60-86 ohms empty. We'll see.

Nope, the supplier called me today and said the part was not available. Our only hope is to modify something to work in our cars. 85/86 have an unusual 10-70 ohm resistance. The later years starting at 87 have a higher resistance around 260 so it won't work properly. So I took the one I received for the 85 carburetor version, cut it off very carefully with a dremel cut off wheel as not to damage the internals by prying. Cut off the existing upper portion of the plate from my sending unit. Then I used a rivet gun to attach the new switch to the old tube. Then I soldered the wire to the contact. The ony thing left was to bend the float so it travels to the same high and low levels. Here is a picture. I'm likely going to test it tonight, but the resistance is correct.

I finally got around to filling up the car and it goes past full. It was a little over 1/8th of a tank and it took 12.5 gallons. Somebody told me this car has a 13.5 gallon tank, but I read it was 15.