When did the heavyweight boxing championship match, for which the Zaire 74 concert was intended to be a major promotional event, actually take place?  
Zaire 74: Zaire 74 was a three-day live music festival that took place on September 22 to 24, 1974 at the 20th of May Stadium in Kinshasa, Zaire (now Democratic Republic of the Congo). Zaire 74:  The concert, conceived by South African trumpeter Hugh Masekela and record producer Stewart Levine, was meant to be a major promotional event for the heavyweight boxing championship match between Muhammad Ali and George Foreman, known as The Rumble in the Jungle. The Rumble in the Jungle: The Rumble in the Jungle was a historic boxing event in Kinshasa, Zaire (now Democratic Republic of the Congo) on October 30, 1974 (at 4:00 am).
October 30, 1974 (at 4:00 am)