Engine harness wiring

[robert91gt]

69' 440 I'm cleaning up this harness temporarily. Prior owner added electronic ignition and a bunch of booger splices. I'm wondering if anyone knows what the red wire is? Looks like it's going back a cross the firewall into an unmolested part of harness. Could it have been snipped and omitted with the conversion? I'm not seeing a red wire in the wiring diagram. Thanks.

 

[pnora]

Not factory. Open the harness and follow it.

 

[451Mopar]

May have been added for a tachometer or electric choke?