Recently rebuilt the quadrajet on my stock 79 z28 (4 on the floor trans). Runs good and eliminated any bogging, but I want to get more performance out of it. Idle/fuel mixture screws were set to 5 turns out. I went to 9 and a half turns out by using a tachometer and looking for increased RPM. Went from 700 to 920, then I brought the curb idle down with the idle screw at the throttle. Wanted to get to 700 but with that screw backed all the way out I could only get down to 740. Is 9 1/2 turns out on the idlle/fuel mixture screws a normal setting? How far is too far? I noticed that there must be a mechanical limitation as well, because the screws are under spring tension and any screw can only be turned out so far before it is just too loose mechanically. Anyone have any pointers for further tuning a quadrajet to gain performance?