<VV> Gas gauge accuracy

[shortle]

My gas gauge on my '69 Convert. #2891 seems to work properly with the exception of when the tank is full the needle goes past the F by about 1/4 of an inch. Then when it's about 1/4 of an inch off E it will run out of gas. Though it is easy enough to rely on it, I would like it to be correct. It seems if I could rotate the gauge about 1/4 of an inch it would be correct but I know that is not possible. I know the tank and sender unit were replaced with NOS parts a while before I bought the car and I have made sure the sender grounding circuit as well as the gauge ground are excellent. Anyone? Thank you for any suggestions.
Timothy Shortle in Durango Colorado