reading the slant six plugs color

Easy way to limit centrifugal advance. Otherwise it's weld up the slots and file to size. (Decreasing the slot length in the advance plate)

The dude who makes them has a website, from memory: 4secondsflat.com
How to limit mechanical advance in a mopar distributor, tuning for street, strip or all out racing, cure that rich stinky idle, win races
I think I read that he is having health issues so not sure if he is active anymore.