Are you sure Grazulis said that? I distinctly remember his write-up on Ruskin Heights mentioning that there was F5-level damage to businesses in at least one area, regardless of the homes.There used to be a thread dedicated to it, apparently:
'Ruskin Heights' tornado (1957)
- 44 killed (500+ injured) - 71 mile track - Debris spotted at 30,000 feet by pilots flying near the storm - Mail from Grandview, MO was found in Iowa (165 miles away) http://www.flatlandkc.org/news-issues/cover-story/60th-anniversary-ruskin-heights-tornado-kansas-city-missouri/...talkweather.com
Grazulis gives Ruskin Heights an F4 rating, but I don't see why it shouldn't be rated F5, I've never seen these automobile damage pics from it before, really impressive.