Hei conversion

Is the Mopar ECU box needed(orange box?)
Not with Davis Unified Ignition as now you have a chevy distributor modified to fit a Mopar.
Did you buy the car this way? Did it run ? You are gonna do a bit of investigation on what and what has not been eliminated in the wiring. Can't help you with that. The DUI does not use a ballast just a key power source.