[Greg Reid]

Jay, looks like you've found the problem. I haven't had a fuel tank sending unit in my hand in years so I'm not sure how that ribbon is attached to the body. Looks kind of like it's captured under that stud with a type of ring terminal?
Anyway, no rust is a good thing if you're planning to solder a jumper in. Seems like a viable solution unless there's something special about that ribbon.
Quick Silver obviously has some experience here...

I would think that sending unit would be available from NAPA...Maybe even GM dealerships. They must have made nearly a million cars that use that same one?

If not, maybe you can find a clean used unit from another car in the classifieds. I wouldn't think there'd be any difference over quite a few years of mid '70s GM cars....At the very least, F body cars for '74.