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Just to clarify.
I don’t always open and hone each bore. If the motor has good compression it gets left alone. That being said, I work on a lot of early Bigtwin/RDs. There are prone to worn bushings in the small end of the rod. I often have to tear down to change a rod (usually the top). While it’s apart, if the cylinder has a heavy glaze, I will hone it and install new rings.
I re-read a couple versions of the OMC service manuals. Some give the spec for the bore as 2.8750, others say it should be 2.8745-2.8755. I assume that the .001 range is the tolerance for a new bore leaving the factory??? I have not found any mention of a maximum allowable size before an overbore is required. Did most dealers assume that if the piston to wall clearance were acceptable, and ring gap within spec, that it was good to run?
In any case. I re-measured my bore. They have more barrel shape than out of round. The port area ranges from .0015 to .0030 oversize. Out of round at any point is .0010 or less. I will put new rings in it and close her up.