I just found the same thing with my 440 that I dropped a valve in when I tore it apart. I did not assemble the engine, it came in the car I bought. Looks like the ring rode along and did not kill the cyl. wall, amazing !
I think with no tension and a shitload of oil on the cylinder walls it would not gouge the cylinder wall.
One of the Turbo 2.2's blocks I acquired years ago had 2 top rings snapped. The blow by was huge. Piston crowns were like orange peel due to detonation and sparkplugs has speckels of alumumn.
