UA 6327 then UA 3754 at Houston
Monterrey → Houston → Waco
Timetable, Houston time
12:30UA 6327 from Monterrey at the gate
11:30UA 3754 to Waco leaves the gate
23 h apart on the timetable, overnight
UA 3754 leaves 23 h after UA 6327 arrives on the timetable: more than half a day, so not a connection we count.