Back in the late 70's my little sister and her husband bought a 318 powered 70 Charger from the original owner with some were in the high 70,000 mile range on it, car ran perfect.
Around a year later they asked me to take a look at it because it was making a weird whirring noise and started using a lot of oil, well to make a long story short the whirring noise was the timing chain rubbing on the front cover and the oil leak was where it wore through. When I took it apart there was not one piece of plastic left on the top gear and that 318 fired up every time and ran as smooth as the day they bought it. Dropped the pan, cleaned out the pickup and pan, new timing chain, gaskets set, a used timing cover. They drove that Charger to around 120,000 miles and my brother in law sold it and used the money for a down payment on a new 1983 Dodge 4x4 truck 318 powered ofcourse.