funny thing, when i added the 8 3/4, and had the new shaft built, they left it almost 1/4" longer than i asked for. went to install it and couldn't get the U-joint past the rear yoke. realized the rearend was just hanging on the springs, (which is not how i measured it). jacked it up a little and it fit fine. that worried me, so i loaded and unloaded the suspension as much as i could to make sure the yoke didn't bottom out. they got it spot on when i had it cut again for the gear vendors though. now i have a 1/2" of slip with the car at ride height
