Not getting 12 volts to coil
OK. I'm sure we can figure this out. May need to look at some unmolested or well restored examples, but lets try with what we have now.
Your 1970 Barracuda originally came with what instrument panel and options ?
Let me clip some pics for my own better understanding of the options.
or
This is your photo of the inside of the bulkhead connector. We see a pair of 4 terminal connectors and a pair of 8 terminal connectors.
which looks like it matches up with this illustration in the Plymouth FSM
So far so good. Now I'm looking at the engine compartment diagrams. In addition to the alternator wiring for the Hemi that you posted, the diagram on the previous page shows four or five wiring configurations depending on the engine and whether an idle speed solenoid was used. None of these use a a connector like the Hemi wiring.
Is there, or was there a idle soldenoid on the throttle side of the carburrtor. Take a photo if it helps.