Using 8 3/4 with /6

If it is for a rear sway bar mount (Hotchkis) then simply get U bolts to fit (2.5" I think) and make a new bracket that mounts to the axle housing. Make sure that you an change it up later. Just use the 3" mount when you get a 8.75 down the track. Most suspension improvements will happen without the rear swaybar.