I am guessing your refering to a P-series saginaw pump similar to what is on GM's and Fords. PSC supposedly makes/made a bracket to allows for a P-series pump to be bolted on to / installed on a 4.0 to replace the TC series pump, I do not know if they still make it, sell it, or if there was ever one available for a 2.5l
wondering as to why you are looking to upgrade? are you planning on full hydro? otherwise, I do not see a benfit to the retro fit if you stay traditional steering.
Quick edit, I think some 99+ 4.0 had a TC pump with integrated resevoir, I do not know what exact model though.