I build a stand alone relay kit for the 70-71 roadlamp cars. It's everything that you need for under the hood. Only thing you would need would be a small, low amp trigger wire and switch to turn them on. I can set up a trigger wire into the passenger compartment if need be. I do everything to the customer spec if it's viable solution.

The roadlamps on a 70 can be on in either high or low beam. The 71 roadlamp relay turns the roadlamps off when high beams are switched on. It's a Fed regulation IIRC, that you can't have more than 4 forward facing illuminating lights on a vehicle.

It's the green wiring in this picture