There isn't a lot of adjustment, Mike. I would first screw the idle adjustment screw in all the way (gently until it stops) and then back it out about 1/2 turn. Then I would start the engine, set the idle speed to 500 and then I would attach a vacuum gauge and turn the idle speed screw counter-clockwise (loosen it) until your vacuum is at the highest level but don't unscrew the idle screw more than 1/2 turn. You might think the engine runs better if your idle screw is more like 1.5 turns out, but you'll be running richer than you want at that point. Good luck!

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end