I had a serious problem with stalling in a couple of vehicles I restored: A 1969 MUTT (military "jeep") and a 70' 340 Cuda. Both vehicles had sat for a long time. It really drove me nuts. They would just hiccup, sorta stall, run, and repeat. No pattern. Sometimes it got so bad the engine would sputter and quit
So I removed the bowls on the carbs on both vehicles. Very fine rust particulate in both bowls. I cleaned the bowls, changed out fuel filters, it would run ok for a time, then it would keep happening. The bowls were full again of the fine rust. So I looked in both tanks. With a flashlight and eyeball, what you could see looked great: The typical clean and grey galvanizing that one would expect, at least in my very limited field of vision.
But when I took the sending units out, I could take my finger, rub it along the inside the tank, and I would get a what looked like red mud: It was rust, as fine as you can imagine. Any in line filter or sock I would run would still let some of it thru. And cleaning and flushing the tank did not help. The symptoms would eventually reoccur: Once a tanks rust inside, its pretty much over and will continue to do so
If you have ANY doubts on an old tank, get rid of it get a new one. The cost of a new one, to me, isn't worth a cleaning or "lining" of an old tank, especially when the tank has to come out in the first place.