Am checking out Arroncakes writeups, as well as other ones I can find on the MS forums

Is the spark output for a 1987 FC going high or low?

On AC's MS2 writeup it is going low, but on the MS3 writeup it is going high. Did something change between MS2 and MS3 to change how the coils operate?

I am seeing both across several other peoples builds and cannot seem to get any replies, and I remember burning out my coils on my Miata years ago because of this setting.

 

There was a change in the circuitry, I am not the MS expert but you do have to go with what is needed for your hardware.

I think in the old hardware the conditioner reversed the signal making high low and low high.

 

Newer MS2 microsquirt versions(V2and V3) and MS3pro's use an adaptive circuit based on the MAX9926 IC .....just to add to what peejay noted above.