Thanks. If I follow the wire that is connected to the +terminal of the coil, I arrive at  the starter solenoid. The outer terminal shows +6 volt with the key on the on position (zero with the key off). The inner terminal shows 0 volt and I believe that is the one that provides 12 volt when cranking (I was on my own and unable to test that).
Where typically would you take the 12 volt feed?

Christian,

Thank you Rich. You are correct, there are two wires to the + at the coil. Not easy to see because they are wrapped together in the same black cloth-like sleeve at this point.
According to the electrical diagram, the one that goes to the ignition switch via the bulkhead connector is 20g and is black and then red-white and has a fusible link somewhere between the coil and the bulkhead connector.
Past the bulk head connector, it is a 12g pink wire to the ignition switch .
Several questions:
1) I can't locate the bulkhead connector under the dash: Where exactly should I look for it?
2) Do you know if the drop in voltage is done between the bulk head connector and the coil (in which case, I would need to bypass that wire between the coil and the connector), or if I need to bypass the pink wire to the ignition switch as well? I tend to believe the 12g wire is probably not the resistor wire.
3) The whole purpose of bypassing the resistor wire is to get 12 volts at the coil. Doing this, I would also bypass the fusible link. It does not sound like a bright idea. Your thoughts?

OK. As to the location of the bulkhead connector, I got some clues.
If I understand well, it makes the connection through the firewall, just behind the fuse box.
How do I access this connector? Considering I am working on the engine compartment side, I am interested in accessing that side of the bulkhead connector.

If your 71 is the same as my 74, you can get 12V at the idle stop solenoid whenever the key is on.

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A quick note to you .If in fact you go with Ignitor III,one of my favorite electronic ignitions systems,you will have to use,install a Pertronix .32 OHM coil,which is required for Ignitor III,as is 1.6 ohm for Ignitor II,and Ignitor I needs 2.8 -3.2 coil..Follow my instructions on running new wire from inside fuse block and you will be a happy camper..       nosal1         Sal C

Thank you for the valuable information. Yes, I am installing the Ignitor III and yes, I have the special coil that goes with it. The access to the fuse box is everything but easy (I am rather tall and my arms are a little too long between the elbows and the wrist to give me much liberty with my hands in there). I was trying to find a more accessible place to get the 12 volt key on. But I will follow your instructions. I have got to find a way. Thanks a lot.

Christian,

I installed both the Iginitor III and the Pertronix Flame Thrower coil, following your directions.
It just works great.
Fires up better, idles better, cruises in 4th gear at 25 mph better than ever.
Can't really tell the difference at high RPM but the thing just works great generally speaking.
Thank you for your help.

Your welcome Christian my pleasure and Happy Motoring..Sal C      nosal1