A half year later I may have identified the problem. The car sat inside a mechanic's shop with the cylinder heads off for about 20 years. The mechanic eventually moved to a new location and the car ended sitting outdoors for a while. There was a small amount of water in some of the cylinder bores when I got it. My hunch is that the some of the piston rings are frozen with rust. I am thinking that the inconsistent compression readings are due to frozen piston rings. This may also be the source of grey smoke and oil consumption.
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