Based on official records, Indiana has experienced three F5 tornadoes since 1950, all of which occurred on the infamous date of April 3, 1974. But there are other tornadoes that have been deemed "near-F5" or actually rated F5 by non-official sources. Here are the tornadoes from 1880-present that are rated F5 by another source or were said to be near-F5 by Tom Grazulis (note that the list below does not include those three official F5s).
April 1, 1884 - Henry/Delaware (rated F5 by Grazulis)
May 26, 1917 - Monroe: about 15 homes were destroyed, some with near-F5 damage
March 28, 1920 - Jay/Adams/Mercer OH/Van Wert OH: homes were entirely swept away east of Geneva and south of Ceylon in possible F5 fashion
March 18, 1925 - MO/IL/Posey/Gibson/Pike (Tri-State Tornado, rated F5 by Grazulis)
May 21, 1949 - Crawford IL/Sullivan: restaurant leveled and cars carried 100-300 yards (recognized as F5 by Nuclear Regulatory Commission, or NRC)
April 17, 1963 - Kankakee IL/Newton/Jasper/Pulaski: near-F5 damage occurred in IL and seven homes were swept away (near-F5) in Jasper county
April 11, 1965 - Elkhart/LaGrange: a dozen homes were leveled in the Rainbow Lake area and intensity was near-F5
April 11, 1965 - St. Joseph/Elkhart/LaGrange - Sunnyside and Kingston Heights housing developments in Dunlap were devastated (rated F5 by Grazulis)
April 11, 1965 - Montgomery/Boone/Hamilton: cars were thrown over 100 yards (recognized as F5 by NRC)
April 3, 1974 - Bartholomew/Decatur/Franklin: near-F5 damage occurred on a Decatur county farm, 3 miles southwest of New Point
A recent interesting case is the Henryville tornado of March 2, 2012. The tornado is officially rated EF4, but thick sections (6" thick or greater) of concrete were ripped up and thrown some distance at one point along the damage path. There is no damage indicator on the EF scale to account for this type of damage but it would likely take incredible wind speeds to do that. The fast forward speed of this tornado means that very strong winds would have impacted any particular spot very briefly, so it is not a case of the wind gradually weakening the pavement.
