i have no educated info on this really.... but i know the axles are a little wider on the newer trucks.... is the differential itself the same to where you could use the same gears? just a thought.... also if you have the 3.55s already i dont think it would be much of a difference really swapping to the 3.73.... if you have 3.31 you could tell a diff though.... but mine has the 3.31 and ive pulled 20K trailer with it and 20s on 34s and it still had plenty balls.... i would just put a mild tune on it and call it a day personally....
2011 F250 6.7 CC SB FX4 tuxedo black, s&b intake, 5" flo pro, h&s xrt pro, tuned by SPE, diff lock override
2008 F250 6.4 CC SB 4x4 lariat dark stone, tuned by IDP
2003 F250 6.0 CC SB 4x4 lariat centinneal, too many mods! tuned by IDP
Shout outs to Innovative Diesel, Snyder Performance, Street Diesel, North Texas Diesel