Million Plus?
C Pancake, over the last couple years of being on TDR the highest reported mileage I've seen by an actual member was in the 350,000 to 400,000 mile range (not sure exactly).
The highest mileage I've ever known of, on a '91 truck, was 1,240,000 miles. This was a guy in Indiana I talked to over a year ago but he has since sold his truck. Internally the original engine only received valve adjustments and a new set of injectors. It was on its second set of injectors and injector pump which was replaced around 600,000 miles. Amazingly he still had the original turbo! He bought the truck new and used it for almost 10 years delivering Dutchman camper trailers all over the US. He was still regularly trekking cross-country even at that high mileage. The engine was starting to use a little oil, a whopping quart every 2000 miles! But he said it ran great! He has since sold it to a farmer in Kentucky and he bought himself a '96 or '98. I need to get in touch with him for an update, and to try and track down the '91.
Vaughn