To answer your question atomarc, no, not until the SM465 4 speed did one come with a internal switch. The 3 speeds were mounted to the shift levers on the column. Installed plenty of these at the various full service gas stations where I worked after school and early in my military service. Shor; if you go the switch route mount a idiot light next to it to remind you to turn it off, that way the local cop don't have to.
