Welcome to the forum.
Since you already have a few modern smokers, why not keep the original smoke unit in the 773? It's a nice engine to preserve.
One small tip. Get a half dozen little tupperware containers (or even bowls) and put the front truck and all its bolts, washers, etc in one. In another do the same thing with the rear truck, another for drive rods, etc. Easier to keep track of what goes with what this way.