[dmjlambert]

There is another short piece of rubber fuel line between the frame and the hard line under the rear of the cab. I recommend replace that since you're replacing the one at the fuel pump. Don't just go out there and squeeze it unless you have a new one ready, or a bucket to put under it and wrench ready to loosen the hard line at the sender, or it might crumble in your hands and accidentally siphon all the gas from the tank onto the ground.

And there is a rubber seal between the fuel sender and the tank, which you can get to by moving the seat forward. The fuel sender is near the top of the tank behind the seat. After removing the fuel line and electric wire from the sender, turn the lock ring counter clockwise. There is a special tool sold to turn that ring, but I simply used some large pliers with jaws open to press against the tangs to loosen and tighten that.

howzzzit mentioned the fuel pump itself, and there is rubber inside it. If the rubber in it is old it could be it was not the type of rubber that tolerates ethanol. Newer formulations of rubber must be used with gasahol. I bought a Delphi cheap fuel pump at Autozone and it has lasted about 5 years now, and I use gasohol, so I think it has the right rubber in it. There are problems with new fuel pumps that I have seen posts about on the forum about them failing fast, and some producing too much pressure and causing carbuetors to flood. So approach fuel pump problems with a little caution and if you install one you don't necessarily get to think you're done with that.

I have a 69 that I park in the garage and it doesn't have strong fuel smell so I think you are heading toward a solution. Be careful, and keep a fire extinguisher handy, and a buddy present and standing by if possible, while working on fuel stuff. And perhaps work on it outside.