My only working MSD was used on my ‘79 Magnum with just stock parts to upgrade it and a custom dual exhaust off of the exhaust manifolds. It was excellent in low speed driving and low speed cruising. I had 2.76’s & 235/60/15’s in all 4 corners. With a Federal Mogual emissions 600 AFB I did squeak out 20 mpg’s and the MSD was very helpful for that last little bit.
