I am not sure if the MSD and Jacobs has the same set up for the trigger lead but I just got throught fighting a similar problem in my Jacobs. I finally traced it down to a spade connector in the trigger lead that had came apart inside the plastic factory cover. Sometimes I had spark and other times nothing. Replaced the connector and now don't get closer than 8 inches to the coil. Just a thought as I said, I am not familiar with the new MSD set-up.
Ron
