More useful info here
https://board.moparts.org/ubbthreads.../199003/1.html
It looks as though the module listed in the previous post enables part throttle kickdown but this can happen at higher speeds than on later setups. The full upgrade would require a later valve body. I believe this can be done with the transmission still in the car.
Andrew's 46RH transmission is probably circa 1992 to 1995 so will have several years of development on a standard 411 unit.