Doug,
I've been there. Sorry to hear it. I finally took out the MSD dizzy and box and installed a Pertronix Flame Thrower III Dizzy and it was like night and day. BIG solid spark, self-contained (no box), and includes an internal rev-limiter. A nice polished billet piece. Got it with the black cap. I am done with MSD.
'Plug n Play' Billet Distributors