Having done more then a few chassis swaps, I see a few things that may be an issue. Understand, these thoughts are all done without the benefit of doing any measuring, measurements could change everything. I find that if you can park the two chassis side by side, its much easier to see what might fit easily, and what won't fit so easy. Match up the front wheels and start measuring.

1) The "B" van chassis has a pretty wide front wheel track. It may be OK with the 1 1/2 ton truck front fenders, but I still suspect its going to put the tires right at the edge of the fenders. Tire to fender clearance becomes more of an issue if you want to lower the front end.

2) The "B" van has a pretty short nose, the distance from the front suspension to the steering column/firewall is very short, and that 47 is not. I suspect the van steering box is going to occupy the same location as the 47 frame you will probably have to use. I just did a 39-47 Dodge cab on a 90s Dakota frame, the van front end is a lot shorter and a lot wider then a Dakota front end. Now, if that 47 is a cab-over engine (COE) then the van chassis would probably work out well. Stretching that van suspension to fit that 1 1/2 ton 47 Dodge might be a real challenge. You might get away with just mounting the van suspension and crossmember to the 47, and come up with something different with the steering.

You might be farther ahead finding a modern one ton with a beam front axle to transplant onto your trucks springs (or move the modern springs as well as the axle). Another thought might be to measure a full size Ram of the front suspension.

The good news is I don't see much of an issue with the rear end. I'd swap in the modern springs and axle, and rear sway bar if one is present.

Again, don't take my word on it, do the side by side park, and measure.

As referenced from the post above, it is much easier to move the sheet metal to the new chassis, but then you loose the frame numbers, if that is important in your state (you may loose them in the parts swap as well). The frame numbers on that 47 Dodge are behind the front wheel on the drivers side. Gene