http://www.moparts.org/Tech/Archive/fuel/34/bulletin34,p15,carb.JPG
Keep tuning you'll get there.
A very WISE man once said to me after I asked him about improving the Holley Design "Fix a Holley and it will work like a Carter."
Did you pull the plugs after the run to see what they looked like?
How smooth did the engine run with the different carbs?
What ignition did you use?