To make it completely bolt on you need to replace the rear axle "bolster?" (tail piece) That would be the part that bolts to the superstructure and has the height adjusting bolts in it. Everything else is supposed to be bolt on. I have an 87' 1680 which is basically just a newer stickered 1480. It was long shoed right when the long shoe came out. There were no tail pieces available at that time other than new, which was too expensive, so the dealer cut and welded the stock short shoe piece and did a hack job of it. Now that used tail pieces (bolster?) are available you should be able to do the whole thing in a short time. You'll have to make extra sure your tailings and grain augers and elevator chains are in great shape to take the extra volume.
Yes, my 1680 started life as a short shoe. It is a bolt on deal to convert, and it would depend on your cropping and climate whether it would pay out or not. Lots of folks still using the short shoe machines with great success, but their crops and harvest climate allow it that way. Also some has chosen to invest the money toward a stripper header for the grains and feel the short those is more than adequate.