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