Prices are going to vary wildly by region, but I would put that truck more in the $3500-$4500 category at best. He says lots of upgrades but does not elaborate. If he means the abomination of a steering wheel then I just hope he kept the old one...
He says 3 owners and 145K miles which is plausible. Those engines will run 500K if cared for, but the injection pump and injectors are only good for 100-150K and may be due for replacement. Parts store replacements are garbage. Even if he says they have been replaced that may not necessarily be a favor. Budget around $900 for new Stanadyne sticks and a pump rebuilt by a reputable diesel shop (such as those available from R&D). Most of the bad mouthing of IDI’s comes from people who have driven with a worn-out, out-of-time fuel system. The maintenance is higher up front but it pays off in longevity, mpg, and a nice strong running engine. Nothing runs like mechanical injection.
SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD
STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering
BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2