I had a low-mile '54 Buick I turned into a daily driver, and ran into this problem. There were a few issues:
The insides of the fuel lines had developed surface rust from sitting dry for 10 years. When the fuel ran thru it, the rust particles dislodged and would flow with the fuel. The rust was as fine as talcum powder. It'd gum up the line, the filter, the carb and the fuel pump. I replaced the lines and it solved the problem.
Second problem: fuel pump was slowly dying. The truck would run for a while, and then the pump wouldn't keep up and it would die.
Third problem: the fuel tank pick-up tube was almost closed off with varnish. I couldn't believe it. It was about 85-90 percent shut. Cleaned it with muratic acid, and it worked.
All of those problems were happening at the same time, so tracking them down was a pain. When it was all done, the carb had trash in it, which also killed the engine and would keep it from running. So I replaced the 2bbl with a factory 4bbl, and the thing ran find from that point on.
-Brad
