Thanks again. This is great info. I like the thought about using the vacuum advance idea. I had wondered if any one had ever set an advance up in reverse to use a boost reference and then I saw that comment. I used to be a big diesel nut with the first Ford 7.3 PowerStrokes. We did all sorts of out of the box stuff, especially when the aftermarket support wasn’t quite there yet.
I'm certain that MSD unit will do the job perfect, but if you're like I am and like to mess with stuff and make unconventional things work, the vacuum advance would be something to fuss with for sure. lol