stock 89 GT 5pd hatchback gears

they are either 2.73's or 3.08's.. jack her up and spin the wheel around exactly once....and count how many revs the drive shaft makes....2 and 3/4 revs = 2.73's and 3 revs = 3.08's
 
Above is correct. The 08's were optional. And odds are decent that they were swapped, so dont go by the door or pumpkin tag.

Good luck.