Is there a way to power a distributor with a switch that is open in the on position and closed when turned to the off position?
That is a tricky one. Those magneto switches are kind of special, especially correct era ones. The simple thing might be to just hook it up and read it backwards (off is on, on is off). But that could cause a problem at some time for somebody.
It may, or may not be possible to flip the cover and body of the switch. It just depends upon how it is made and would have to be evaluated.
A modern fix could be worked out using a relay. It could be difficult to not drain the battery when turned off.
Drive carefully, and enjoy, W2
What year is the car and what switch are you trying to use to power your distributor? If you are using a T dash switch typical of 1920-23 then it is rather easy.
We need more info. Do you have a switch you want to use?
Wayne's right, a relay would do the job, but if a toggle switch would do, it could be as simple as mounting it upside down and rotating the "on - off" plate.
It is a Briggs and Stratton magneto switch, it has a lock position an off position and an on position. Lock and off have continuity to ground the mag. On position is an open circuit. I want to use it on a speedster. It is a very nice switch with headlight and magneto switch and key to lock the ignition.