Fair enough. A matter of curiousity as to what was done by the factory.
Several differences mean that its not appropriate to directly translate that 65amp alt '72 Satellite wiring to a '67 Barracuda, Dart or Valiant. It appears we are looking at an option group that includes an perhaps an optional electric fuel pump and other electric powered accessories. That said, I'll give it a shot.
1) The gauge changes for the A1 wire (fusible link notwithstanding)
A1-10 R carries the current to the main splice (distribution point) for all the normal systems. 10 gage was considered plenty for power demands of a fully optioned B-body.
Presumably its 10 gage on both sides of the bulkhead connector.
R6C-6 BK may be larger to minimize losses oever the distance, especially in the hot engine compartment. In addition to the power needs tied to the main splice, at times it will have to recharge the battery. Therefore a larger size makes sense.
2) The 16ga size of A1A wire (starter relay to red terminal on the ammeter)
In a normal use, the wire only carries current to recharge the battery. As long as the battery is not run down, its not alot of current. That's the thinking anyway...
When starting, power will go through the other way, but again, its not a lot. It will be the amount needed by the ignition and the starter relay - maybe 5 amps.
Protection has been moved to the battery side of the starter relay. It doesn't say what size that fusible link was, but since the relay draws a fair amount of power, it wouldn't surpise me if it was 2 sizes smaller than the 10 gage, rather than the 16 gage. My guess is that the 16 gage line to the ammeter also had a fusible link even this diagram doesn't show it.
3) The terminal block where the 6ga R6C wire from the alt splits to A1 and R6B. I've found a p/n 1842267 which I think is the terminal block for the L/N 65 amp alt (not sure if a must have).
I'm with Rob, I don't see the reason for replicating this system, unless you are recreating a '72 taxi or ? with the same options. It's interesting to study to better understand the strategy and borrow ideas as appropriate.
In dark red is the power flow when the engine is running and the battery is charging (dashed lines) with the setup as shown.
View attachment 1715134494
My guess is the terminal block represents a further modification of the bulkhead bypass (wires through grommet).
The next diagram shows the powerflow if the wires were not cut and no power went through the bulkhead connector. However if the bulkhead connection was there, along with the bypass, it would work pretty much same except the power would divide along the paths the paths of least resistance. Without knowing where the A1 line from the ammeter goes, its impossible to guess whether there is current in it....
View attachment 1715134495
edit: Perhaps the dashed A1-12R was a way to partially bypass the ammeter during start up? or engine off? Maybe for an electric fuel pump, or two way radio?
