I haven't pulled the valve cover yet, but I did check all the spark plugs on that side. Only #8 showed anything slightly "unaverage".
Maybe the headers are now the difference in what I hear, but it is definitely only the drivers side that has anything remotely abnormal.
Basically, I believe that I ruled out anything that has to do with the ignition (cap, points, rotor, wires, etc), but isn't the popping backfire a problem when a cylinder sees a spark at the wrong time? or maybe residual spark somehow?
Still do not know why the idle will not come down. The only thing that I can think of is that I installed the butterflies on the throttle shaftbackwards???
I will have to pull the carb next because once the idle set screw is backed all the way off, the choke fast idle cam is backed off, etc, this thing will not respond with an idle change at all. It acts like part throttle is open. It is getting air from somewhere right? You can see the secondary butterflies as the engine runs with the blower carb hat off, and they are definitely closed.
Another item. I did check the vacuum at idle when I had the two barrel on the engine (at idle it was steady at 18 in).
One thing I will say...this engine seems to be very responsive to throttle changes with only the mechanical advance (I plugged the vacuum advance port on the carb plugged)
thanks for all these ideas
Daniel JessupLancaster, California
aka "The Hot Rod Reverend" 
check out the 1955 Ford Fairlane build at www.hotrodreverend.com