There's going to be fab work either way.
I know the body swap can be done, but I question how "born there" it will look.
An axle swap can be done be with perches and look stock. Motor, trans and transfer case mounts are relatively easy also.
With the body swap this would be my initial list of concerns:
What's the frame contour, is it going to look right, or look like it was just made to work?
How are the front clip, cab, and box mounts going to work? Quite a bit of fab work there to do the 12 mounts.
Wheelbase, it's not going to be the same. You will have to relocate the rear springs to put the axle where you want it, shock mounts and brake lines may have to move with it. Is the hump in the frame generous enough to accommodate the move? You will have to have the drive shaft length modified to work.
Engine, time saved by not having to build mounts may all be lost due to it's current placement. Front axle will determine that, and will it be just the right fit between the radiator and firewall? A 6BT doesn't leave room for error in that regard. Move the engine and you move the trans and transfer case and the associated mounts. Not much different than just fabbing them to fit the original frame.
Bumper, make some mounts for it to work with the new frame. Also will have to move or fab a rear cross member if you want it to resemble stock.
In my opinion, I'd much rather keep the stock frame and move everything from the donor to it. Just makes more sense to me.
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