[41ford1]

Back to your sending unit and tank questions. I made a disk the same size hole pattern as the fuel sender flange of 1/8" hardboard. It was mounted in the same way as the sender, gasketed and screwed down. In my case it was put there only for a clean out process. I did not coat the inside of the tank.
If you wire up the sender and power the gauges you should see the gauge move with the position of the sender arm. Be sure to ground the sender flange. Check the float for leaks. Put it in hot water and look for bubbles. If bubbles are seen replace it. Floats are available as well as complete senders.