I don't see where it has been mentioned that you will need your tail shaft to have the two mounting bosses for the flat shifter plate. Here is a link showing what I'm talking about. Not all trans had them. Moparts on the Web - Main Index
I didn't know that until the guy that sold me these parts mentioned it. Of course my trans does not have the mounting holes. I think it came out of a truck.
I do have a spare 727 that does have the mounting bosses. Is it as simple as swapping out the tailshaft housings?