I learned something new today working on a Dominator carb, I have a wide ban on the car and had the AFR up close to 16.2 to 17.4, I enrichened the idle mixture screws 1 full turn and that slowed the idle RPM down 150 to 200 RPM It was at or close to 1200 RPM at first and slowed down to around a 1000 RPM when I fattened it up to around 13.8 to 14.2, it started stinking so I leaned it back out, that speeded up the idle back to 1200 RPM or so