Gas gage reads full all the time!!!!!!!!

So I got in my '69 Barracuda the other day and the gas gauge was reading beyond full (maxed out). I researched the problem here on FABO and many said to disconnect the wire at the tank and see what happens. Well when I disconnected the wire at the tank the gauge went to empty....so I guess the sender is bad. I checked on ebay and found many senders (from $39 to $109) for my car.....my questions is, "Which sender is the best to buy", I don't want any more problems. The car is mostly all original (survivor) and I'm sure that the sender is the factory unit?? It's been a great car with no issues.

treblig