65 Dart gas tank leak

A new gasket is ~$3. I think you can get just that at rockauto or ebay. If your sender isn't working (common after 30 yrs), a new sender is ~$45 on ebay and comes w/ a new gasket.

You might need to roll that into your fuel pump issues, since you can get senders w/ a 3/8" supply tube and a 1/4" return tube. If an EFI-type electric pump, you need a return to the tank.

Many posts here on all of the above if you search.