1966 fuel sending unit

The previous owner of my mustang told me he thought that he had installed the fuel sending unit upside down, because it reads past full with the wire connected. Is it possible to do this? With the sending unit wire disconnected, guage reads below empty. My next attempt will be to run a jumper from the sender to the framerail to see if there are grounding issues. Does NAPA carry the sending units, or can you purchase the O ring or gasket if my existing sender can be fixed?
Thanks
 
i dont believe you can install the sending unit upside down because of the shape of the tank. The sending unit has the pickup that angles into the tank. It cannot be put in upside down or you cannot put the whole assembly into the tank. Sounds like some old gauges that still work to me. Napa does not carry the sending unit to my knowledge. Autozone started getting in some stuff like that but I will warn you its something like $25 more than Dallas Mustang or any other mustang supply house
 
xoxbxfx said:
i dont believe you can install the sending unit upside down because of the shape of the tank. The sending unit has the pickup that angles into the tank. It cannot be put in upside down or you cannot put the whole assembly into the tank. Sounds like some old gauges that still work to me. Napa does not carry the sending unit to my knowledge. Autozone started getting in some stuff like that but I will warn you its something like $25 more than Dallas Mustang or any other mustang supply house

Yes, I just did this and the unit will not go in upside down! Keep in mind this is 45 year old Falcon technology.

HistoricMustang
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On my '66, even the new sending unit had to be adjusted to get the right gauge reading. A bit of time and minor bending of the float arm and the gauge can be made to match the amount of gas in the tank. I worked with 4 gal. (1/4 tank) in the tank, drained it 3 times and adjusted the float arm each time. Now it reads nearly perfect with what is in the tank.