I am not a fan of the MSD ignition muliti-spark system.
I did install one on a Subaru boxer 4 cylinder years and found no difference except much more radio interference.
I do still have a MSD ignition delay 'add-on' box that allows continued use of the oem ignition but allows up to 20 degrees of ignition retard. I bought this MSD single spark 'black box' after finding that the Mopar Performance PCM computer for a 1995 Magnum 5.9V8 advanced the ignition timing so much that it would ping when at full throttle starting at 3200 rpm in 95 degree summer air temperatures even if Sunoco 95 octane gasoline were used.
If you want to try lean burn carb jetting, I would suggest using Iridium alloy 'tiny tip' sparkplugs with wide gaps.
The Pertronix 'Second Strike' aftermarket ignition would be a better choice than the MSD, because the first strike is still the long burn time from the inductive coil.
Tiny 'vortex generators' in the intake manifold port ends might be a low cost mod that would help during lean afr
note that these vortex generators, called 'Wheeler VG design' are actually two airplane wings side by side with each wing at the angle that causes a vortex similar to what you see on the Space Shuttle
Mitsubishi has this paper in pdf file form that shows two other shapes that can be used as vortex generators that I call 'shark fin and 'Kamm-back' shapes:
You can see similar single wing vortex generators on the top of some BMW outside rear view mirrors, and on the bottom of the Mercedes ML500 SUV outside mirrors
