Well Guys. If you've been following along, here is my latest update. I pulled the gauge cluster apart and cleaned off the paint behind the fuel gauge segment to make sure I have a good ground. Put it back together again, turned on ignition and it read 1/2 a tank full. Switched off ignition and it remained at 1/2 full. Went down to the local gas station, topped up the tank (only took $6.00) and it still reads half a tank.
Came home, shut it down, disconnected the wire between the sender and the tank. Momentarily turned on the ignition and got full scale deflection past the full mark. Turned off the ignition and reinstalled wire and turned on ignition and gauge went down to register full. Turn off ignition and gauge continues to read full. Will have to take truck for a drive and see what happens next.