Who is running a Quikfuel 450 on their Slant

So here are a few of my symptoms, the carburetor required me to turn in the idle mixture screws almost all the way into the carb to get the highest vacuum reading. So I am only about one half turn out for the air fuel mixture screws. The car occassionaly idles a little too high even though I added slack to the throttle cable and turned the idle all the way down. It almost acts like it is returning to high idle but not as fast, so maybe my return spring is not heavy enough. I can get the idle to lower when I give the throttle a quick snap. It hesitates slightly when I put the pedal to the metal.