Need help with weird MSD distributor issue

[davepl]

Asking for a friend, who has FAST throttle body fuel injection.

Using a known good old MSD "Ready to Run" distributor, the motor runs fine.

Using any new, replacement MSD "Ready to Run" distributor, we've tried two, and the motor backfires and pops and snorts and runs like crap, as though the timing were all over the map.

Thing is the computer has no control of the timing, and nothing is connected to the distributor.

Any ideas on what could be consistently wrong or different with the new ones?

My only guess was maybe timing was locked out on the old one and so the computer wasn't adding "double" timing, but that went away when I found out the distributor was completely standalone.