Factory High Stall Converters

There is no such thing as a factory high stall converter.
That's complete and utter nonsense. All of the factory high stall converters are stamped "Hi Stall" right on the housing. I've seen a lot of them. Just like the chart above reads, the factory high stall converters were "about" 1000 RPM over stock. I don't know where your information comes from, but it's incorrect.