The wires in the 68 good? If so why are you changing so much??
Why not just add the electronic ign and dual fld wiring to the 68 harness? It's cake to do. Only a few wires. That way you can use your stock starter relay and all.
Looks like I can sacrifice a V8 underhood harness and if I can keep all the proper circuits intact, I'll have a harness that should plug into everything with a brown and a dark blue wire which will go to Q and N respectively. If I work this right, I should be able to make these connections at the original ballast resistor location, thus minimizing the amount of splicing. That should take care of the electronic ignition and voltage regulator. I'll have to modify the oil pressure and temp sender wires cause they are in different locations /6 to V8. I'd also have to change the neutral safety switch on the V8 trans to the old style switch. Upside, no messing with the starter relay, downside, I'd still have to dress the new wires into the original harness to make it look right. Also should remove the original ballast resistor/coil wiring and the regulator wiring.