The only thing would be if there is a third hose attached to the pump. That would be a return line to the tank. If that line is blocked, there is the potential for fuel pressure to go too high and push the needle off the seat in the carburetor. If you look down into the air horn while the engine is running, you will see fuel dribbling in from the accelerator pump nozzles. You could also prove that by pinching off one of the rubber hoses going into or out of the pump.
A little known problem that causes stalling with carburetors, assuming you still have spark, is a plugged pickup screen inside the gas tank. It will collapse, typically after ten to fifteen miles, and restrict the amount of fuel that can get through it. Sometimes you can blow that screen off by removing the supply hose from the pump and blasting it with compressed air. Be sure the gas cap is removed so you do not expand the tank. The symptom of the plugged screen is gradually losing power and you will feel some surging for anywhere from a few seconds to a minute or more. With a little cranking after letting it sit for fifteen minutes, it will run again for another few miles.
If you do find that you have no spark when it stalls, you might suspect the ignition module or the pickup coil inside the distributor. The module tends to fail instantly when warm; no sputtering or gradual loss of power. The wires on the pickup coil flex each time the vacuum advance turns the plate that coil is mounted on. As a potential test, you can disconnect the vacuum hose at the distributor and plug it. If it no longer stalls, it could be because the wires on the pickup coil are not flexing and breaking the circuit. That is not necessarily a conclusive test but it can provide some clues.
Monday, April 18th, 2011 AT 8:03 PM