I'm currently driving a 99 F-250 SD with the 7.3 out of my 01 that got totalled. The 99 had 536,??? miles on it when the transmission broke something in it when I put it in reverse one day so I pulled the 7.3 engine and transmission complete out of the 01 with 312,??? miles and dropped it in last spring. I still have the 99 engine in the shed to use if I ever might need it. Dad's truck is a 02 7.3 with just over 200,000 miles on it.
@FixItCharlie
The 7.3 is a great engine. Drove a 2002 F550 box truck that was brand new. We would load that truck up heavy. It never drove any different loaded or unloaded power wise. It just dug deep and kept pulling.
I drove it for a year until I quit then it was used up until 2013 when they retired it. Injectors were the only problem they really had with it.
When it was the primary it got a 15k oil change every 45ish days. It was constantly on the road.