Wait to hear from Dave & Jerry and others.
I worked in a shop in the early 70s and was told that a 216 would be lucky to make it to 50,000 miles without at least new rings and a head rebuild. Usually a engine rebuild and over-bore was done by 50,000.
Most of those trucks did not do much long distance or highway driving. Start/stop and many warmups and many short trips took a toll on the engine.
If your engine code matches your title/registration and the engine never had to be bored; and, the engine is not a replacement engine with your code put on it, it could be a low mileage truck. Have you checked the date casting codes on block and head?
