Starter neutral switch on all '50's Ford cars is located near bottom of steering column. It may be out of adjustment if the two retaining screws are loose. But if it worked before and the screws are tight, the problem is most likely in either the worn out rubber bushing in the lever at the bottom of the shift tube. You could also have excessive wear in the shift link rod that goes into the transmission shift lever.
The original starter neutral switches lasted practically forever if they were properly adjusted and there was no slop in the shift linkage.
The repro switches are made in china. You can have everything perfect and the switch will only last a year at most due to the substandard materials and methods used in their construction. At least one of the repro outfits I use has quit advertising them as starter neutral switches and now they are calling it a backup light switch due to the constant customer complaints about the failing switches.
Also unfortunately, the rubber grommet for the shift lever is no longer offered by the repro parts guys, but if you are creating, you can make something that will work properly. My shift rod was worn halfway thru at the bottom where it goes thru the hole in the transmission lever. I took it off, ran a bead of weld at the worn spot and ground it down perfectly round so it would fit back in the hole without any slop.
