This post isn't is it a sensible idea but rather would it work. 7427 would be the pcm for this discussion. If you had a second unit with map/power/grounds all connected and all the spark settings at zero and you connected the ignition output of the original pcm into the signal port of the second pcm and the ignition output then to the hei 8 module. Would it work? The one problem might be instead of the pcm planning the next ignition event it might end up two events. You can probably tell it is chilly out today and I am not in the shop.