I don't know what you are using for a clutch pedal. The older neutral saftey switches were wired through the clutch pedal. The switch would mount to the clutch pedal bracket and close when the clutch was depressed. Here is an example of one for a 1979 Chevy truck. If you got one like the one pictured below, you would only make up a simple bracket to hold it in place. On the cars with auto trans the neutral switch and back up switch are made together in a cluster that usually mounts on the column for column shift cars, or in the center console.
That E237 is for auto trans.
These kind screw into the trans:
