I'd borrow a known good old style analog 6AL box and try it.
I don't know what to tell you to try w/ the digital box b/c I tried everything I knew of and never got it to clear up.
I think maybe your old 6AL crapped out and the new digital box is just having a fit for some reason.

There's a guy in North Carolina that repairs MSD products...Pat Collins at TechWest Racing. 704-995-4286 He's repaired boxes for me in the past and has done a great job.

I've also ran the Blaster 2 coils horizontally for years and never had a problem.