Buy a Ram 3500 with the Cummins and enjoy! Good luck with wiping the ongoing grin off your face:B
Seriously it will pull at least 3x better than your 7.3L and get at least as good fuel mileage doing it if not better. And you will have the legendary Cummins reliability.
I bought my truck after owning 3 Fords over the past 20 years including a 7.3L and 6.0L and have absolutely no regrets. If you're going to tow over 14k lbs give serious consideration to a dually. Our truck handles our 16k lbs fiver with ease up AND down all types of overpasses here on the Westcoast.
Good luck and please keep us informed.