Who has the highest mileage Ford V10 motorhome?

As mentioned there may have been a few failures of this type over the years, but they are certainly few and far between.

If you Google Ford 6.8 liter durability you'll see there are a number of threads in different forums on the subject. They are quite popular for utility and delivery vehicles. Both UPS and FEDEX have used them for several years. Most have gone between 250,000 miles and 3000,000 miles without major maintenance or failure