[Eric 1151]

Since you haven't mentioned an amp gauge problem prior to the MSD Digital install, I am assuming the gauge was ok. Since the only change is the MSD install, that's where I would start looking. The problem with the amp gauge on SPF's was that the wiring was designed for an idiot light, not a gauge. Changes at the voltage regulator was the fix. Not sure what they were. Anyway, that's what Mike from Dynamic told me, over 10 years ago.
Eric