Ignition problem???

In my testing, what I have found is;
If you have a fully functional factor Dual-Ballast ignition system wired like it was a 71 Duster, running a 5-pin ECU, then;
1) it will run with any factory ECU off any SBM or slanty car; at least all the ones in my collection of about a dozen did. and
2) it will also run any 4-pin ECU; the ECU side of the Dual ballast just "deadheads" at the empty socket ......... which means you always have a spare on board, lol..
3) On the few 5-pin ECUs I tested; they all ran on battery voltage for extended periods of time,
4) the 4-pin ECU Orange box I ran, would start to malfunction at over 18 or so volts, and under about 7 volts. Between 8 and 18 it seemed to run fine on my car. But I noticed no particular performance change in that 8>18 voltage range.
5) After my Orange box eventually quit, I changed my Amp to what is now, an old Jacob's Ignition, dash-mounted, dial-back unit, and
to a square-top, Accel Super-Coil, which, 22 years later, both of them are together, and still working fine,
6) I recommend NOT to try and run an E-core compatible coil, on the factory style NOT CDI, amp. Most of those coils need a Capacitor Discharge of 525 volts, and do not do well on 8volts continuously switched.