The Stovebolt Site Forums The Shop Area Engine Shop Carb, points, or ??? Stalling while driving

That explains a lot. Over time the gas flow is slowing down dramatically. Thus the bucking and dying. The question is why. Assuming the lines are clear (and if they weren't, the flow would be steadily slow not increasingly slow), there are only three possibilities I can think of; fuel filter, fuel pump or sending unit.

A filter can fill up with trash and slow the flow to a trickle. Then, when the flow stops, the trash settles, and the flow will be fine for a little while after it first restarts.

Take the fuel line off the inlet side of the fuel filter and rerun your test. Does it still take as long to fill a pint? Then the problem isn't the fuel filter. If it fills fast, replace the fuel filter, but keep in mind that something is plugging it up.

Old vehicles get varnish in the fuel tank and the lines. Unless all of that is thoroughly cleaned out (or the parts are replaced), the varnish will continue to break loose and plug the filter. (Varnish can also screw up a fuel pump.)

If it's not the fuel filter, you've isolated the problem to the fuel pump and the sending unit, remove the line from the sending unit and put it in a container filled with gas. Repeat the test. If the pint fills fast, it's the sending unit or the tank itself. It it doesn't, it's the fuel pump.