Wiring doesn't change between a slant 6 (NOT a V6) and V8, except for the length of some of the leads- the "schematic" of it remains the same. Just extend/reroute some of the wires.
This assumes you will run points, and the factory mechanical VR and alternator. If you're upgrading to electronic or other aftermarket ignition; or higher output alternator and electronic voltage regulator, the same mods would apply as for any other car.
But as for the difference between 6 and 8, basically nada.