I have made the Granada to '57 swap several times but not on a '54. The Granada to '57-'64 and on early Mustangs has been documented several times. You can even buy new Granada stuff on a web site. I have also done the rack and pinion swap on '57-'64. You will be really happy with it.
Versailles discs are the same but the spindle has a larger bottom hole for the ball joint.FWIWSpeedway has offered the tapered ream for several years and recently Summit (maybe Jegs) also offers the ream. It does not take a mill to open the tapered holes. A little turning by hand will do the job!!!
I used the reamer from Speedway, chucked it up in a 1/2" electric drill, put my spindle in a vise, measured the depth I wanted and drilled it. Worked really out pretty good.