I had a few problems with the improvised EFI pump and pickup that I installed in the original fuel tank. I installed it in the factory pickup hole for convenience.
I had problems with a pump that started to squeal and the seal leaked more than once. I don't get how people kept the seal from leaking over the years. It is such a crappy and awkward fitting. The other issue was having no gauge pickup -- no idea how much gas was left.
First attempt was to install a stock 65 mustang fuel float attached to the same mount as the pump but it leaked.
Next attempt was to cut 2 holes in the top of the tank and mount the pick up and pump from the top but the stock opening on the bottom leaked again. Getting tired of this.
I went to just weld the factory pickup hole shut and saw that the inside of the tank was pretty rusty so that settled that.
Finally, I bought a brand new EFI conversion tank from Tanks Inc. along with the correct EFI pickup tube plate and gauge sending unit. The tank has a baffle tray already welded in so no more risk of starvation. This new pump mounting plate has the pressure and return lines plus the vent fitting. These tanks are very nice replacements and look like the original. It comes with in a silver paint (or might be powder coat.)
Everything fits great and no leaks. The only catch is now the fuel lines and fittings are in trunk. Not ideal. Given the history of these trunk mount tanks, I will need to install one of those rigid safety covers one of these days. For now, its back to annoying the neighbors and leaving posi marks everywhere.