Since it looks like you'll be in the Cummins area for load, check out Goerend Transmission and SunCoast Performance. They specialize in the build and pieces for the 47 and 48 trans so that they'll live under high torque and loads. Also there may be someone in your area that caters to the Cummins trucks with auto trannies, ask around. You could also get in touch with A&A out of Indiana.
Build the internals to diesel specs, this especially goes for the OD unit, it has more clutches in the Diesel/V10 application vs. a gas job. The OD unit I have behind my Cummins Ram has more 2 clutches/steels in it vs. the standard diesel/V10, this requires a step in the thick plate.
The only negative I can see for that convertor is the stall speed might not be what is optimum for your 440?
