I have a complete 55 FOM and a early 70s FMX so do all I need to do is use the 55 convertor and front pump in the early 70s trans along with redrilling a couple holes and thats it or is there more that will be needed.


Butchering up everything I can get my hands on in Dayton Ohio

That will take care of the front end.  In the middle, your throttle pressure linkage becomes kickdown linkage and have to be dealt with.  Also, your '55 column shift linkage will not permit manual low gear, but that will probably make any difference to you.  In the rear, the mount will probably need adapting.  Your '55 driveshaft yoke will not fit the FMX output shaft, and the FMX yoke will not fit the '55 driveshaft, so a driveshaft will have to be modified or a new one built to suit.  The original driveshaft will probably be the  wrong length anyway.  Good luck.

John - "The Hoosier Hurricane"

I forgot to mention, you will also have to provide manifold vacuum to the transmission modulator.

John - "The Hoosier Hurricane"

dont you need a merc torque converter as the ford is course spline input shaft.

The column shifter can be made to work by adding an extension to it. I made one that used a small hole on the end that attached to it (with a larger flat washer) and the other end could accept the stock grommet. As for the old pressure kick down; I made a "slider" on the end of the stock rod at the top linkage and adjusted it to actuate the trans kick down just before wide oper throttle.
The photo of the shifter extension has no holes (marked with a felt pen) and has out guides so it won't move. I welded 2 when making one.
The inside trans gear indicator shows a green and white dot on each side of the "D" as my trans is a 62 medium case Cruise-O. The extension made this happen.
If your old trans speedo came in on the bottom of the out put shaft and the new one the top of the out put shaft your speed may run backwards, but not if your new trans has the correct inner gear direction.
These are just things the hot rodder puts up with...

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

Darrell, you are right about the different splines between the '55 and the FMX.  I didn't realize a Merc converter would fix it.  I just installed the '55 input shaft in the FMX.  Unfortunately, that requires a complete disassembly of both transmissions to swap input shafts.

John - "The Hoosier Hurricane"

I am going to have the FMX rebuilt so the 55 converter will be no problem,right now with the C-4 I can get it in low so I have a found a 70s truck with a FMX to grab the shift arm from so the original linkage should go right on.    The C-4 that is in it has a 70s truck arm and no modifications to the shift rod and as for the kick down linkage I should be able to find something to work,the 272 I picked up has a 2 bbl and I am planning on a 57 intake so I am on the hunt for a 55 or 56 4 bbl linkage.   My 55 has a 56 firewall so I can use either linkages.


Butchering up everything I can get my hands on in Dayton Ohio

john i never did the swap myself but just assumed thats what people were doing.the merc from 55 up has 27 splines same as the rest where ford has 17 so i just figured it would work.anyone looking to do this swap make sure you get the long fmx or youll need another driveshaft.the mustang torino etc have a short one and the linkage is set up for a floor shift so is upside down.