Trying to take another stab at this and could us some input. My quadrajet has always been adjusted all the way out on the idle speed screw and still idles 900RPM. The choke is set right at about 1500 RPM when cold, timing is good, carb was rebuild 2 years ago and runs great. Anything I'm missing? Would like to be able to adjust RPM all the way down to 600-700.