Fix your initial timing. Sounds like your mechanics fell out of the 1970's and set it up timing via total method which is not the best way to do things.

Do as Y07 has suggested. More initial will clean up the idle and get it to run better at idle with more vacuum. You'll need to modify the distributor curve so your total number doesn't go out of range.

This car has the same cam, easily idles at 850 in park and 750 in gear, pulls 14". IIRC, it has 16-18 initial. If your car won't idle that low, the issue is likely in your ignition settings.