Well, I had 2 7.3 PSDs... one in a OBS 4dr Dually, with a 5spd.. and the other was a 99.5 bastard(newer engine, older suspension)....
Both were STONE ROCK RELIABLE....
And neither was stock.
My second, was closer to stock, custom programming, blah blah blah...
Anyway, as long as you have the forged rods, and have a brain between your ears... you can work these motors up to 500rwhp(costly I will admit), and still be reliable....
I could never get good mileage outta either of mine, but, that was okay... until diesel went up to 5.50 a gallon, and my now ex wife finally said... its gotta go...
There is TONS AND TONS of info on these motors...
Only problem I ever had with mine, was injetor sleeves cracked on 2 injectors, allowing fuel oil to get into the coolant....not a major issue really...but, needed to be addressed.
GOOD programming(DP Tuner, Jody is the best with these things, and Tony Wildman outta DFW, TX, is who did my tunes on my S/D) If you want, send your ECM to Jody, and have him burn a 100hp program into it, and be done...
IF you have an auto....
DO YOURSELF A FAVOR, and get a triple disc convertor, and an aftermarket valve body.... those are the 2 weak links in the 4R100....
FWIW, the biggest thing I dont like about my truck? The Dodge wrapped around a great motor. The Super Duty has to have one of the nicest interior layouts.. period...
Chase