Grigg, good thought on the distributor. In this case that cylinder is always dead and each time it was checked, the spark was good.
It will be easy enough to check the intake chamber in the head when I get the manifold off on the way to removing the head.

Jerry, I know you think carburetors should go through life like hermits, alone. But many years of working on imported cars, of which 80% had a minimum of 2 carbs, says that if you size them correctly, they work very well.