Hi Matt,
The inline 6 harness can be modified to work with the V8. The differences are mostly in the lengths of the wires and how they're routed. Some wires might need to be shortened. Others might need extensions spliced on in order to reach the new component locations. Just be careful to keep the wiring away from hot and moving parts.
Starter, alternator, and ignition (distributor power feed) wiring uses the same hookups for both engines. The sixes originally used an electric choke and wiring for that ran through a special oil pressure switch (so the choke wouldn't stay powered up if a person left the key on w/o the engine running). The factory setup on V8's used a hot air style choke (heated by the crossover passage in the intake). However, you could utilize the 6-cyl electric choke wiring on your V8 if you're using a carb with an electric choke. You'd need to transfer the oil pressure switch over from the old 6-cyl though. I don't know if it has the same size threads or not (might need an adapter).
