Idle issue on my 440...

have done a LOT of carb work on AFBs i think Carter says that the shaft should have NO more than .004-.005" clearance. i would put bronze oil-lite bushings in them.. if you dont know how DONT try it. the main tricks are seating the throttle plates. which if not done right will make your trouble worse. and the screws are not easy to get out and then you have to be sure they dont come out later. the big Q you need to ask your self is do you have a return spring that is to stiff?