90's Durango - Mechanic told friend to scrap

The 4.7 was a good engine if the oil was changed religiously and it was never overheated. Those that were maintained ran forever and those that were neglected failed in a long list of ways. Just about any time a gasket fails or steel parts come loose in an aluminum head it's because of overheating. They also didn't tolerate sludge well. This engine was initially an AMC design, but development wasn't finished until several years after Chrysler bought AMC.