bought a new MSD distributor
Limiting mechanical advance at about 18*, allows more initial which will help idle quality.
Should be a bag with 3 or 4 of them in it along with advance springs.
Check out instructions at MSD site or summit if you don't have a hard copy.
I'm assuming it's this one.
http://www.summitracing.com/parts/msd-8546/overview/make/plymouth