Can’t find any part number on the internet about my 8.75 742 case gears

Another way to tell the ratio is to mark the pinion and ring. Rotate and count the turns on the pinion and see how many turns it takes to move the ring gear one full revolution. If its almost 5 turns of the pinion then 4.88 it is. Thats a steep gear judging on the ring gear thickness.
You can also use the same method with the rear in the car. Just mark the tire and count the turns.