8 3/4 I.d. ?

If your looking for the ratio....jack-up the rear off the ground and mark a tire at 12:00. Put a mark on your driveshaft and rotate the tire once...at the same time count how many time your driveshaft turns. It will put you in the ball park

IE 1 complete turn of tire may = 3 1/4 complete turns driveshaft = 3:23