Hey Tom, there is a pic posted here on CC showing that motor with what is claimed to be a holley fi system. Check the photo gallery for Back in Black
You will see it in there. Mystery solved?
In his photo description it states 1000 cfm holley throttle body using 36 lb/hr injectors and a Commander ECU. That should give you enough to have a conversation with holley for info.
The holley site has a tuning manual for commander 950 circa 2004 that may help you
https://documents.holley.com/techlibrary_r10149-7.pdf