When I rebuilt my carb (670 street avenger, engine 60 over 454, cam RV) I adjusted the idle mixture screws with a vacuum cage plugged to the intake port for the transmission. I adjusted the screws according to the best vacuum/highest reading at idle. Was that the correct way or did I luck out "and find and acorn"? Truck is running fine. I saw something the other day posted saying the adjust with the car in gear. Gage I was using was one that is also used to bleed brakes.