Should be no problem. Biggest deal is the floor pan of the 25 doesn't have the hump for the offset transfer case of th 40. Mine had a FJ40 four speed case in it and all they did was trim a brace. John is doing that with Project Old Fart. '59 and earlier had a different mounting pattern for the front fenders to frame.
If you just want the "look" we can probably get you some round wheel openings and soft-top door openings to weld into a 40.

And, if you search you may find a description of how Gene builds a 25 bib.