rear disc from grand cherokee on a 8 3/4

while I don't know the difference in rearends, I am going to try to get them to work on an 8 3/4. I have already drilled out the center of caliper bracket to fit the over the bearings...and not by much 20 or 30 thou... I have access to a machine shop so will see when the time comes...I am going to give it a go in about a month from now.