Remember those spring loaded, arm type switches used under the floorboards on old Chevys. The arm just goes above the brake pedal. Somebody? maybe Mac's, listed them in their hot rod section. Bill W.
(The existing wires should reach O.K. & it just screws to the bottom of the floorboard with 2 wood screws. The switch arm "might" have to be bent a little, but it bends easy, without breaking! I know a man that put one for his clutch pedal to operate a little buzzer, so he "knew" when he was ridin' the clutch!)