One more idea. Is this with a quadrajet? If so, can you tell me how much effect the idle mixture screws have? In other words, if you close the idle mixture screws all the way does the engine immediately die, or does it lumber on? (If it's not a Q-Jet but rather a Holley the symptoms might be the same, but the solution is different.)
Also, when you "blip" the throttle, do you get a puff of black smoke out the pipe?
I know you think the motor is starving for fuel, but is might be the opposite.
