When I supercharged my 8BA I put a Q-Jet from a supercharged Buick on top of the blower. It had all the running symptoms yours has. I took it to a friend who builds nasty motors. He said it was starving for idle air. Opening the throttle plate more took it off of the idle system. Sooo solution was to drill very small hole in each plate and progressively make them bigger until it idled. It worked great. You might want to check with some one local who knows before you try this.