Ray it isn't peak hp that you look at for trans application, it is peak torque output which the 413 has in spades above the 5.9.We need @transman to chime in if he is around about the best way to modify one of the 46rh's to live in our application. No way am I spending 7k on a trans build. That said I am capable of building it myself so it will just be parts expense for me.