Probably best going down the route of having a new one fabricated from either alloy or stainless. The original lead coated steel (turnplate) from which they were originally made is no longer easy to source.
I've repaired petrol tanks quite successfully by steaming them out with a steam cleaner. It does also get the crap off the outside. I still work on them out doors ans always wave my oxy torch around and in the filler pipe stub. Arwyn
Hi Arwyn! Hope this finds you well.
Steam cleaning is an excellent procedure! Outdoors and out of the car makes the job so much easier with a so much better result. There are other key tasks that require the tank to be remove. For example, an effective old trick is to toss in nuts and bolts and shake the tank to have them thoroughly detach unwanted flakes and rust. Obviously impossible to shake the tank and flip it over to drain debris and liquids when the tank is still in the car.
Yes, I agree again, A new tank is the safest and smartest but it is beyond many. They don't have the usage to justify the cost/hassles.
b]Alloy tanks gives me the creeps.[/b] Alloy goes from solid to liquid in an instant without warning a warning sign. I watched for an hour while liquid alloy rain drops spray fell like rain with each minor explosion after our accident..lighting up anything it could in a big circle. I was forced to stay for that until the fir department arrived. Other trad-burned owners told me the same since. I realize that alloy is cheap and easier to work with but it should be banned as a fuel tank material unless it holds a racing bladder. Actually, having paid for both, a sturdier affair like mine now is smarter and less costly. As you know, the cost difference between metals, their grades and their gauges, is immense. And having an easy tank to remove opens up a lot of options.
You’ll likely have the Old Ford lever style fuel sender (assuming it still works)… this would be an ideal time to consider a more modern and reliable set up … it just means a slightly different fuel sender bolt pattern. You mean the one made by, and stamped Smiths? Arwyn

I am using an old Smiths lever arm sender again. After using a hitech Centroid sender for 16 years,
https://centroidproducts.com/ The old Smiths are a relief, albeit with their very weird ohm pattern to fit their arc trajectory.
I also used a made to order VDO sender. But they are not adjustable and I was just so happy I could eliminate the foam so I joyfully celebrated with a Smith's)

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Good to have you here.
Lorne