distributor recurving ?
Because of the cam I suspected that the idle need to be that high. Back in my Buick days I ran Q-jets for awhile and I had a similar problem of having the idle screw cranked in to get it to idle. The problem was the small primaries can't move enough air closed down to let it idle. My fix was to adjust/bend the secondary closed stop so the secondary butterflies were just cracked open to let more air in the motor. I was then able to close the primaries down some.
Chuck