and save the two files for the "these are" AFTERMARKET NOT FACTORY wiring diagrams. They are "handy" and "easier to follow" sometimes, but are NOT always complete
Now let's go back to the 73 Dodge manual you downloaded. Go to page 8-128 which is the engine bay wiring for a 73 Coronet/ Charter, and look there in the upper right hand corner
Notice on the right side end of the ballast, (in the photo) THE TOP AND BOTTOM are jumpered together with a short wire. Find this on your in-car ballast. THAT POINT is where you jumper in 12V from battery to "hot wire" the ignition. THIS MAY BACKFEED and light up the gauges
If your alternator is REMOVED make CERTAIN you tape off and safe off the wiring going to it
THIS STUPID NEW SO CALLED NEW AND IMPROVED SOFTWARE ABSOLUTLEY SUCKS!!!! for someone trying to answer a serious question. You CAN NOT READ the op's question while you are attempting to post an ANSWER!!!!