Carb or ignition ?

mbaird said
I don't think I can get the plates closed any further . I have been conscious of that .
Rpm at idle is about 750. RPM drop of approx 30 in gear .

If it came across like I was suggesting that, I'm sorry.
Bold added to the crux of what may be the issue.

Mattax said
Since the idle mix screws are sensative and the vacuum is strong the throttles may need to be opened a bit more at idle rpm. This will increase the fuel contribution from the transition slots. Then the idle mix screws should be less sensitive. Open them up until the engine is strongest in gear (least drop in rpm when placed in D).

RPM drop of 30 is good. A/J may have a better sense of this cam than I do.
We're both suggesting more throttle and that may mean less initial timing. I was thinking 16 but maybe its going to be strongest at 14* 750 rpm.
Open the throttle, see what happens with respect to rpm.
Then take a few degrees out of the timing or whatever it takes to get back to 750 rpm. Fiddle with the mix screws - should need more open.
Test it shifting into Drive.
Also whether its burning your eyes.
Then see what the AFR meter says just for the record.