Wow! After reading all of these problems you all are having I feel we need an "Ann Landers" or "Dear Abby" type section for this forum...
Younger folks that are not familiar with the older vehicles, are used to seeing some newer cars go up to 150K or more miles with no major engine problems. Other than the usual tires, batteries, brake shoes, etc. cars last longer now. But, in the old days, and especially on 40 year old vehicles, you were lucky to get 60K out of an engine without some sort of major work like cam, timing chain, valve jobs, rings, etc. In those days we would check the odometer and anything in the 60K or higher reading we'd hesitate to buy.
I remember reading an old article about 350 engines. It was saying that the cam should be replaced after 50K to 60K miles if your engine was sputtering, misfiring and/or had loss of power. The lobes were notorious for going flat on these old engines.
I guess it's just the times are a changing for the better when it comes to automobiles.