First, lets identify that you for sure have a 1947, there are some issues in the exchange that may make it harder to accomplish.
1947 unique features:
3 speed on floor, not on column
No provision for column shifter (it has a shallow indentation at the steering mast)
Emergency brake is a lever action next to the shifter on the floor
No emergency brake on the left side.
The gauge cluster is a one year only and will not correctly fit in the later cab and visa versa
The upper cowl does not have the indentation for the water to run off the sides, instead it will overflow into the engine compartment (the engineers missed the mark on this one)
The other features 47/48 are:
Frame mounted gas tank (see other comments)
Body mounts (see other comments)
Windlass crimp moulding
Seat size
There are some additional minor differences, but they will not matter. I think the emergency brake, cab mounts and gauge issue should be addressed before you commit to the swap. None of these should stop you from doing it though. If you are not using a column shifter, then the shallow indentation will not be an issue. The emergency brake can be relocated and you can reuse the parts from your 51 cab. The gauges are probably gong to be reused from the 51 cab so the two lower mounting tabs will have to be relocated to equal proportions (comparing the gauges will make sense)
If it is a 48 cab, the body mounts and the gas tank are the only major changes and the swap will be easier. They corrected the cowl drain system too.
