This can be tricky since there's two different shrouds for Panteras. The early one is much larger but I think the condenser inside is the same. It also takes a different trunk insert with a bigger, removable rear bulge. You've avoided the problem altogether by not using a fan shroud.
Note- to use the huge swirl of air passing over the rear of the car that at certain speeds presses right up against the rear bumper, DeTomaso arranged the AC condenser to suck air from the outside, thru the condenser and blow against the sloping rear surface of the trunk insert. The exhausted hot air then get deflected down toward the pavement in a loop and avoids being sucked into the AC unit again for a second pass. Running without a trunk insert probably degrades the AC output, and reversing the condenser fan direction definitely does so..