:welcome:
Both engines have the same componants so there will be no real problems.
You have a couple of options
1) cut both plugs off, buy a connector plug from an auto store and fit it to the wires
2) get some terminals and some jumper wires then run them between the two plugs and wrap it tight in LOOM TAPE not insulating tape
Or variations of the above I have seen all sorts of things done.
I prefer the jumper method mysef as it allows you to go back.
Rather than go insane trying to work out why the almost correct wiring diagram does not seem t fit.
Take the cover off both engines
Both will have a single wire from the reguator to the batery ( usually fitted to the hot side of the solenoid )
Both will have a single wire that goes to both ignition coils kill wire
The only difference will be Vanguards usually have both a + & = wire to the fuel solenoid and Kohler only have a + and use the engine ground.
mark the engine side of the plug with where each wire goes to then fit the engine wires into the corrosponding position inthe plug.