UA 638 then VA 8393 at San Francisco
Chicago O'Hare → San Francisco → Miami
Timetable, San Francisco time
15:35UA 638 from Chicago O'Hare at the gatealso AC 4116
08:15VA 8393 to Miami leaves the gate
16 h 40 apart on the timetable, overnight
VA 8393 leaves 16 h 40 after UA 638 arrives on the timetable: more than half a day, so not a connection we count.