The original Delco Remy paddle switches were used on many GM applications from the late 30's to the mid 50's.
They work quite well on the original 6 volt systems but,not so well on systems that have been converted to 12 volts.
There are still alot of good used & NOS ones out there.
http://members.cox.net/mothertruckeraz/heaterswitches.JPG