Anyone Familiar With a Blue Wire w/ Yellow Stripe Along Firewall?

a. This is a connector commonly used with a Chrysler magnetic pickup distributor
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b. as mentioned, the blue with trace was commonly used on the connector used with a Chrysler/MP electronic control box connectors.

c.1. That '71 diagram is not a great one. Start with the ones in the factory service manuals.
c.2. You will need to draw your own ignitition circuit since your car has been modified twice.
c.3. There is no advantage in eliminating the ballast resistor when using an MSD. But if you want to, two piggyback terminals and a jumper wire will do it.

For c2, you can start with this schematic if it helps you with layout.
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2.1 if the car has a chrysler ECU on it, then maybe its worth keeping the pentagon shaped connector and wires as back up.
d.2 If you're not going to use a Chrysler ECU as backup, consider removing the connector. Its just one more thing and extra connections to accidently ground or cause other wiring failures.