Those are the original factory wires for the pos side of the coil.

The "sheathed" wire is a resister wire, and that would NOT be correct for the msd distributor, which needs a full 12 volts.

You could cut it out and replace it with a 12 guage stranded wire, or leave it there and also install a new wire from the + coil to the spare IGN terminal on the fusebox.

The yellow wire should stay in place.

 

Jim,

If I leave it there, should I connect it to the coil, or would it get too hot and possibly burn?

 

The yellow wire was used to bypass the resistor wire during crank to give the coil a full 12Volts for easier starting.

You'll want to consult your documentation for the MSD box. Some use no ballast resistor (or resistor wire at all). Others need a full 12V to the ignition module, but a ballast is still needed for the coil. The documentation should clear up the confusion. But I suspect you will want to replace the resistance wire with copper and use a ceramic ballast resistor for the coil if your ignition unit calls for it.

Jim is probably more familiar with the MSD 6A than I am. It probably doesn't need a resistance of any sort. I just don't want to mislead you so I encourage you to check the documentation.

 

The MSD does not need a resister wire or ballast. Their coils do not either. It's still a good idea to read the directions rather than blindly trust a stranger with a text box.

Leaving the original wires in place won't hurt anything. The new wire will handle the current, and that way you can go back to stock should you ever choose too. It's been a LONG time since I've seen those original wires in such good shape, it'd be a shame to cut them.

For some reason, I'm remembering that 67's do not power the IGN circuit with the key in start, and without the yellow wire you have no power to the distributor. I could be wrong, it's been 25 years since I had a 67.

 

Two items not looking correct in the bottom picture.
1. The crimped butt connection - the black wire to the purple wire. The OE purple wire is to the "S" terminal on the starter solenoid. Black wire is extra. Where does it go?
2. The ATC fuse holder by the distributor? Its purpose is ?

 

Thanks for the input guys.
Jim, I won't cut those stock wires if I don't use them.
Everett, the black wire to the purple was a PO part of what I am fixing! That black wire goes to the ignition. The fuse holder is part of wiring connection for the AC.