Where Does This Wire Connect?

Just posted about this 66 Valiant project. Car has the 225 in it. Car will turn over but doesn't fire. While checking it over, we came across this loose wire. It appears to be the wire off of the coil (see the yellow arrow) since it is rolled in that harness down the side of the head, but I have to admit I do not know where it should connect. There are no other obvious unconnected wires anywhere in the engine bay that we see. Would appreciate any help with this.

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