Take if from me- I'm a big Chevy person, and own a Duramax. But I will tell you, that 7.3 is the best diesel ever put into a pickup truck along with the old 12 valve Cummins! 86k miles????? Haha! That truck hasn't even been broken in yet
That's an easy million mile truck! They may be pigs and not very fast, but it'll tow anything you hook behind it with ease. Friend of mine has 130k on his and it's been trouble free.
Run good quality oil in it (Shell Rotella, Chevron Delo, Mobil Delvac,) get diesel from good gas stations, keep the batteries good, and you'll never have a problem with it. If I was a Ford guy and wanted a diesel I'd get the 7.3 before any other.