kill switch

Planning on doing something to slow down the average car thief given how easy it is to hotwire these old cars.

What I am thinking is running the heavy gauge wires which run to the ohm meter through the "rear air" toggle switch. Does anyone know the rating of the factory switch for a 1971 Plymouth duster?

Any other thoughts on how to best do a kill switch that isn't overly obvious?

Thanks,
Bryan.