Hi,
 Currently I have a tired 2 speed Merc o Matic in my 1954 Monterrey. I looking for info if a FMX will bolt up without any adapters? if someone can point me in the right direction regarding resources on this subject will be appreciated.
Thanks

If you look at a stock 58-up Ford automatic indicator on the steering column the Second one below the neutral had a green dot at it. I believe this was to tell previous owners that this was the “drive” to use since the older Ford auto trans did not do this.. I do not know when Ford stopped this but for sure was not used with the C-4 or C-6.
The first D under N was a carryover from the earlier transmissions.
Since 6 spots were now needed on the column indicator of my 56 I had to lengthen the shift arm on the column and the shop doing the work shortened the arm on the transmission.
Your 1 is my L. The governor and vacuum modulator determine when it can stay in a gear along with what’s selected. I do not know how that works. I’ve never tried to hold mine in second gear.

56 Vic, B'Ville 200 MPH Club Member, So Cal.