Where can I find a Neutral Safety Switch

I have a brand new Borg Warner trans installed.. Having trouble at times getting it in and out of N or P. The trans people have narrowed the problem down to the Neutral Safety Switch, which I know for sure is 60 yrs old. 1954 Hudson Hornet Cpe 308. Used would not be preferable, but at this stage I can't be too picky.. Would Al have one or Jason, Vintage Coach. Appreciate any suggestions.