Make sure the two ferrules on the module are connected to ground [ usually via a heat sink ].
If this has been done, then I think it is time for a new module.
In case you are unaware, MSD make a HEI module # 83647 that gives a hotter spark & also has a built in adjustable rev limiter.
It is grounded via the aluminum heat sink and I also have a ground wire going from one mounting bolt to the alternator case but I can try to make sure both bolts are grounded.
Module is brand new out of the box although I know with electronic parts that doesn't always mean good
