[PetChemMan]

It could indeed be a leaning condition caused by a sticking PCV valve, or other vacuum takeoff from the carb or manifold that is leaking. Even power brake boosters can cause huge vacuum leaks.
Try eliminating potential vacuum leaks one by one by plugging them. I know these intermittent problems are difficult to solve. I mentioned before that I had a stalling problem on my Olds caused by a choke that was too rich, and a vacuum pulloff that wasn't working. The combination caused the choke plate to close , and stalled the engine, and would not restart until I stuck a screwdriver into the carb to keep the choke plate open until it warmed up.

Your statement that the acclerator pump well is empty is interesting, since it implies that the float chamber is empty too. Double check that to make sure the jets are above the fuel level, since I've been fooled by looking into the accelerator pump well.

I had two problems with fuel filters that are worth passing on. The first was an aftermarket filter that had too fine an element, and clogged after only a few miles of driving. If the engine sat for a few minutes, it would restart but then stall again a few miles down the road. Switching to a name brand filter solved the problem.

The second problem was stranger by far. It was a fuel starvation problem that would begin only minutes after cleaning and reinstalling the carburetor. Some sort of fine contaminant from the fuel tank was going through the stock inlet fuel filter, but was then accumulating in the carburetor and plugging the idle system. I would find the fine white particles in the bottom of the float bowl. I solved the problem by installing an aftermarket spin-on remote fuel filter designed for diesel trucks, with a 5 micron rating. Tractor supply stores usually stock those filters.

I suppose it's also possible that your fuel pump is faulty. Install a fuel pressure gauge in a "T" fitting in the line at the carb inlet.