I looked very carefully at doing the same thing on my 2009 Fat Bob. Here is what I discovered:
- Left side Switchback shift controls would bolt on exactly.
- Right side brake control would likewise bolt on EXCEPT ...
- The mufflers on the FXDF sit about 3/4 inches further outboard compared to the switchback thus the footboard would interfere with the muffler. To correct that a 3/4 inch shim at the frame mount would be required to move the switchback right side control further outboard.
- The shim would then require the forward end of the rear brake push rod be brought 3/4 inch outboard as well. I don't know if there is sufficient play at the master cylinder so that no modification to the rod is required, or maybe the rod would need to be bent out a bit, or something else.
- All of the above sounds perfectly solvable until you measure the spacing between the mounts on the switchback's forward and rear footboard brackets. On the switchback, they are exactly 10 inches and on my FXDF (where those mounts actually exist, plugged with something), those mounts are 10.25 inches apart. On both sides. So the floorboard brackets, whose spacing is determined by their mounts on the underside of the floorboard, will not mate with the mounts on the FXDF frame.
I concluded I need custom fabrication of boards and/or brackets to make it work.
You should perform similar measurements on your FXDC and see if the same issues exist with your frame. Check muffler clearance to the floorboard, spacing of the frame mounts, and compatibility of the controls.