This “idle air bleed” modification is something that needs to be left to a serious professional. You start drilling out holes you better make sure you know what you’re doing. It’s not like this new carbs with the changeable air bleeds. Check to see if they are plugged up first. If you install a dual sensor wide band o2 system on your car, it will help. There are gifted individuals who can tune by feel, so to speak, but they are not new at this. Get the screws turning and get a wide band O2 unit and play with the carbs. It will help.