Beating Jack Brisco for the NWA World Heavyweight Championship on December 10, 1975, in Miami, Florida, for a few reasons. First, this made him and Dory Jr. the only siblings to hold this title (and still hold that distinction as of January 1, 2013). Second, back in those days, the person who would be NWA World Champ was decided upon by nine people, so there was more of a consensus on who'd be the champ. Third, this would be the same title that Ric Flair would hold almost six years later on September 17, 1981.
Winning the NWA ECW Heavyweight Championship/ECW World Heavyweight Championship twice, once on December 26, 1993 at ECW Holiday Hell 1993 against Sabu and reigning until March 26, 1994 at ECW Ultimate Jeopardy 1994, and the second time on April 13, 1997 at Barely Legal against Raven and reigning until August 9, 1997 at Born to be Wired 1997 against Sabu in that No-Rope Barbed-Wire Match (that match that not only required both men to be cut out of that barbed wire but also that match that Paul Heyman said he didn't want any hardcore ECW wrestler to attempt again.)
Terry Funk vs Cactus Jack in the finals of IWA's (Japan) King of Deathmatch tournament. The match is not the for the faint of heart, but cemented both of them as THE absolute legends of hardcore wrestling, bar none.