Lots of good info here.
A couple things to add, hopefully not get you sidetracked.
These were set up with an idle solenoid to allow 1000-1100 RPM at idle, then shut it down with the key off to prevent dieselling. A bigger cam will only make the idle harder. It can be done, but it's a balancing act.
Are you getting any vacuum to the dist. at idle?
With a lot of initial advance as mentioned, any additional timing that gets pulled out will cause a stumble. Try to adjust without vacuum advance, then try it with...

Good Luck!