According to the Delta timetable effective November 1-December 14, 1985:
Miami-Atlanta
6:10am-7:47am DL 780 L-1011
9:20am-10:54am DL 817 727
11:05am-12:39pm DL 460 727 (SatSunOnly)
12:55pm-2:35pm DL 82 L-1011
2:25pm-4:05pm DL 738 757
6:05pm-7:43pm DL 786 DC-8
8:00pm-9:40pm DL 380 767
Atlanta-San Diego-Ontario would have been flight 423 departing ATL at 8:45am and arriving ONT at 11:13am on a 727.