OEM AC question

[Dead Parrot]

Other things to check:
Make sure the heat/cold flapper is fully shut. Doesn't take much slop to let a lot of heat escape into the AC side. The heater core is normally hot all the time so the flapper adjustment is important. It is behind the glove box.
Is the vacuum operated door on the passenger side working? That is the one that lets the recirculate feature work. Reusing the already cooled and dried air from the cab helps with cooling. It should be open when you have the AC on "Max AC" or similar. Labeling varies for different years.
Probably a silly question but when the engine swap happened, did the vacuum for the cab controls get connected, including the vacuum ball?