100,000 miles was a milestone when your truck was built. And a lot of maintenance was involved to get it that far. That would include a whole bunch of point filing and resetting in between point changes, spark plug resetting and changing, about 10 valve adjustments, a whole bunch of oil changes, among other things. Your truck must have been well cared for.
It would be hard to figure an average but you can bet most didn't make 100,000.
