The longest tornado path for the day was 21.9 miles through parts of Bureau, Lasalle and Lee Counties, IL in 1951. Note: The NWS Chicago in a summary stated that the path was closer to 25 miles long.
The SPC and NCDC only mention Bureau County. The path based on the coordinates does go through Lasalle and Lee as well.
Found differences in the rating. SPC & NCDC lists as F3. Thomas Grazulis in his Significant Tornadoes book list as F2. The NWS Chicago in a Summary page on the tornadoes that occurred this day also list this as an F2.
Most of the damage was found at Spring Valley. Six homes were unroofed or torn apart and the second floor of a two-story brick home was torn off. One person was killed in front of the destroyed railroad depot. (Grazulis, 1993)