I went overkill for my sending unit...I have the original 5/16" unit which I am popped out for a 3/8". Both setups were installed the same way. I have a 14gauge wire soldered to the sending tube below the rubber hose. From there it goes to its own dedicated ground on the frame. I ran a wire all the way from the sending unit, into the harness, and to the old fuel gauge.

With my old gauge it worked but I had restored a second cluster professionally and it still came up just below full tank. This was about the time I swapped units.

I have a brand new brass float from a Ford thats a perfect match for it. Should get around to doing that task soon. Would like to have fuel when I am driving