Someone else that knows this part better than I do could probably chime in, but I seem to remember a small pin or very small tube that sticks out of the block. I dont know what its function was, but it prevented me from rotating the housing to only a few degrees. The instructions about the changeover had me cautions about breaking that tube off, as the author made reference that he (or maybe it was someone on here) had broken it and it was a MAJOR PITA to repair. I think the tube stuck into a little recessed area in the housing, basically restricting it to that one position....cant remember...been too long.
Since I needed the jeep right after the job, I didnt have time to explore how it was made or to make any modifications. The option I would rather have done is to braze a nut on that damn t-60 bolt that holds it all together. Whomever designed that needs a good thrashing.