65 Dart gas tank leak

Ditto on the lock ring. The ones that come with a new sender are not thick enough and cause a leak. If you don't re-use your old one, most people have to use 2 rubber gaskets and/or bend the tabs in.

I don't follow your issues on the electric fuel pump. Photos of where it is installed and description of the plumbing and pressure regulation would help us comment. I have an electric EFI type pump on 2 60's Mopars with no issues.