I'd bet my lunch that there's no US-spec jumper thingy in your headlamp wiring, we're just muddying the waters.
What DOES happen with some Indian restorations however, is that they will chuck parts meant for later models on (not necessarily a bad thing), so what ought to be on your bike might not be what was actually fitted for a 1970 model (the 500 engine being a classic example).
Now if the Indian has retro-fitted a post 1999 lighting system with AC headlights (the sort that only works with the engine running) things get a little more complicated, though there will still be a way of carrying out your desired modification.
So on reflection, we need to know a little more about your electrics.
What sort of switch gear is fitted, both to the headlamp casquette AND on the handlebars (might say Minda or Magura)?
How many wires are coming off the alternator stator, and what colour/color are they?
Let's see if we can get a handle on this.
A.