Those box's cause more problems than they are worth. The reason everybody ran 2 was due to the high failure rate. They do not like heat, low voltage, welding anywhere on the truck, water, vibration....
Just to Bert it up, if your getting your tach signal for the EFI from the MSD, that could be a issue to.
If I had known it had an m.s.d I would have told you to take it out. They work o.k. in a points style ignition system. Other than that they are trash. Actually I dont like their coils either. Quality control is non existent with that company.
Will I be the first one on this website to admit that I have no fucking clue what anyone is talking about when they talk about mechanical issues?!?!?Stock electronic ignition is fine for your use. If something fails parts are cheap and easy to get. But run it for now.