If the threads on the tank and the brass pipe are in good shape, you can put axle grease on the threads which will allow the tapered threads to mesh together to make a perfect seal. The grease won't seal it, it just reduces friction so that the parts will do what they are supposed to do with less force applied. You should use a small pipe wrench for this pipe. Curved-jawed vice grips designed for pipes will work too.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission