Fuel Tank Question: '60 Val

Are you sure it's not the sending unit gasket or filler tube seal?
Aftermarket sending unit lock rings are notorious for being incorrect (too thin and flimsy) and leaking all over the place.
Well, well, well Professor Fate. After pulling the tank, and it did look pretty thrashed from 64 years of road spray, I went about doing everything but investigating the leak, which I presumed was major.

Since there are no good condition 1960 Valiant gas tanks lying around, anywhere, I looked into contriving a fuel tank from scratch from a place that does that locally, but they didn't want it because of the curve in the tank for the wrap-around of the spare tire well. Then I had the bright idea of why make a curve, when a smaller dimension right angled bracket shaped fabricated tank would accomplish the same end- until I crawled under on my arthritic knees and realized the space between axle and well was impossibly small; no doubt why they made the tank a wrap around.

Then we thought about putting a fuel cell into the very large spare well. That looked promising.

Just for a curiosity, and since I had the tank off anyways, I filled it with water. And filled. And filled. At some point the water level exceeded the inlet port and water started to back out- but it kept on and on and on after I had shut the water down. It was almost as if it was doing a reverse siphoning effect. Also, a little trickle of water ran down from the level of the sending unit.

So, why it allowed me to fill the tank on several occasions before without this over-wash (of gasoline) I can only guess. Bad filler gasket, as Professor Fate asks? Therefore, if I can fill it with maybe ten gallons (15 gallon tank? Maybe??) that would negate the leakage problem, excepting for sloshing while accelerating or stopping.

I don't like the idea of a twenty gallon unsecured cell in the trunk. God forbid I wreck, or get hit, then I will be getting a gasoline bath. Or should I just say to Heck with it and go with the cell? That tank does not look to hold more than 15 gallons if filled to the very top- and it reverse siphons out if overfilled.

Advice please?

sending unit.jpg

valiant tank.jpg