determining undocumented miles 300d

[Mesalm]

I was wondering if any of you guys had any interesting methods for determining a ballpark figure in say within 50,000 miles or better, on an 617.95 engine. In the case of a P.O. that changed the odometer in which the miles were undocumented from replaced odometer and the miles of the replacement odometer put in. Some of the cars repair history is known and can be inferred.
I was thinking something like the timing chain stretch or some other internal engine parts that last 100,000's miles The problem is assuming the previous owner changed oil regularly etc. etc. The trick is the ease of measument without an engine teardown and then the inverse accuracy of it's measument.
I'm not trilled about the North American insurance accutaries that use something like, what is it, 12,000 miles driven per year for indiviuals in the US. Using that formula my 1982 300d would have 384,000 REAL miles. 32 years X 12,000= 384,000