360 FBO Ignition no spark

glad it's working. for now keep the spare ECU in the car, easy swap if you do get sidelined. defiantly sounds like a wiring issue. i've chased the same thing, that's why i asked about re-confirming the failed ECU.
you can't always, but try not to make more than one change at a time when your looking for a problem like this, makes it hard to know what fixed it