I had two thoughts, one that the lead from the igniter to the non firing coil is broken and the other was that somehow the Procomm dip switch was set for 360 instead of 270. Did the lack of spark move with the spark coil input?
AFAIK the pickup fires off the stator and the igniter software interprets the pulses and directs them to the appropriate coil. Different stators for the two engines but the same pickup coil. Since the 360 is a single input, dual output coil the igniter would only signal one coil.
Grasping at straws here Ian with a couple of guesses.
