Looking at used Ford F-350 high miles

My mechanic has a 6.0 used to pull his race car. His take is that the truck is just sickening to think about. He has no faith that it will get him to and from the track, on any weekend, without needing to be towed. The resale value is horrendous, and he has far too much time and money wasted keeping it running to just dump it. He also has a large fleet maintenance customer that had a pile of 6.0 F250s on the road. Their bean counters watched the repair costs, and determined that dumping them at the end of the engine warranty was the best business decision. Between down time, and no longer having Ford pick up the tab for keeping the things running, they had to go. This is a company that expects 300-400K out of their typical Chevy and Ford heavy pickups and box trucks.