Rough Idle and stalls

With everthing you said, especially the backfiring, I suspect a loose head. Have a buddy do whatever it takes to get it to run. Take one spark plug wire off, then put it back on. If you do this to all of the cylinders, it can tell you if there is a leak. If the engine comes close to dying when the plug is yanked, the cylinder is good. If it makes almost no difference and the engine is still running, there is a leak. If both cylinders on the same side of the engine are "Bad" I would have to tell you that you have a loose head. If it is just one cylinder, or the two are on opposite sides of the motor, adjust your valves. Mine are currently set at.016 clearance to make up for the expanding metal as the engine heats up. If the adjustment does nothing to the cylinder(s), You have a burned or mis-seated valve. If all of the spark plugs make quite a difference in the opperation, then try adjusting the fuel mixture. The accelerator pump squirts extra gas into the engine when the pedal goes down to avoid stalling on acceleration. So when you pump the pedal, all your doing is raising the idle RPM and introducing more fuel. My adjustment screw is the smaller one on the side of the carburator opposite of the generator. Turning it to the front of the car (left) Increases fuel, and vice-versa. Only turn it a half of a turn each time you try to start it to avoid flooding. If you suspect it flooded, because it will not fire, just remove the spark plugs and crank it a few times, then put them back in. My 67 Bug got the loose head problem 3 times and the symptoms you list fit perfectly. Hope this helps in some way or another, but please check for a loose head before doing anything else to avoid causing more issues for yourself. Good Luck