The early floor shifter neutral safety switch requires a slot in the transmission lever shaft - some of the C4s from the 70s don't have the necessary groove cut in the lever. If that is the case then the transmission mounted switch won't work. You can mount a switch on most shifters or make a bracket to mount one on your shifter.
Justin, It is a shifter arm but it is called a manual lever or selector lever. It all serves the same purpose. In england they call a car a "Motor" and they don't go for a drive, they go motoring. Language can be very limiting and confusing.
your just being picky, i dont think he plans on putting the switch on the trans right away. You can get it real close to the stock one so there might not be a problem
WELL,,, just gotta say it,,,, between my shoulder and my hand that is on the shifter of my C-4,,,,, THAT would be called a,,,, shifter arm ,,,,,