Originally Posted by IceTrojan

IF everything goes on time, you can comfortably walk from the far end of the T4 pier to The-Terminal-Building-Formerly-Known-as-T8 in about 15-20 minutes, all behind security.

Originally Posted by TWA884

Are you checking luggage? I have yet to receive checked bags from AA at LAX sooner than 30 minutes after my flights arrived at the gate. In that case, you also need to factor in the time that it takes get to T7, 10 - 15 minutes, check the bags at UA and clear security there. That would make a 1:20 connection rather tight.

If you have only carry on luggage, I fully agree with IceTrojan.