I've swapped O/D gears into standard boxes. I personally like the O/D boxes, but I swap the O/D gears and mainshaft into a standard small bearing, 307, A-833 main case to get away from the loose countershaft and larger 308 input bearing. That way I can also swap The O/D into a standard A-Body bellhousing. I just happens that the input shaft from an early or late 3.09 gear set is the same as one of the two O/D gear sets. The input shaft is combined with the 4th gear on a standard A-833 or 3rd gear of an O/D gear set since the O/D gear is on the O/D main shaft. All standard A-833 main shafts, including the 3.09 main shaft, will take any gear set, except the two O/D gear sets. If you want to run the O/D gear sets, the only main shaft that will work is an O/D main shaft. Reread the article.
