Holley Idle mixture screws non responsive?

As Crackedback said if the engine dies when you turn in the idle screws THEY ARE WORKING. You adjust them by turning them in until the engine slows down then back them out until it idles smooth but no more. He's also right about it being a big drop in rpm but as he said if the converter is stock that's the way they act with a fairly large cam like the 284/484. A buddy of mine has a Challenger with a 440 with the 284/484 cam in it and it only pulls about 8 inches of vacuum in gear and it wasn't that good until I modified the dist. weights so it could run more initial timing without going to much on the top end. He also has a stock converter and we have to idle it at 900 in neutral so it don't die when dropped in gear cause the stock converter is so tight it pulls down hard on the engine in drive. AT 900 in neutral it drops to about 650 in gear. He needs a looser converter. I had the same problem in my 360 at first and slapped in a 3k stall converter and now I set the idle at 775~800 in neutral and it only drops to 700-725 rpm when I drop it in gear.

You may have to modify the advance weights in the dist. so it doesn't have so much centrifugal timing and that'll allow you to run more initial. That's something you always do to a engine with a perf. cam.