I have a 53 GMC with a vacuum 2 speed. It is totally different than the electric shift box. I think the only way would be is to swap the whole rear end which would be quite simple. I haven't tried to shift mine. I had a vacuum leak so I just plugged the line at the intake manifold and put the axle in high range. I don't need a two speed because I have a GMC 270 and all I do with it is haul trash. It has a dump bed similar to yours. One of these days I have intentions of chasing down the vacuum leak. I assumed the post made by 59Shorty indicated that he had found a complete electric rear end and was wondering about the wiring.
