Yes I have the GN 8 1/2" rear with 3.90's. I'm not wanting to go that far as to weld new ends on the axel tubes. Maybe I'll get a new posi unit. Mine needs a rebuild, In my burnout I get the drivers side to stop spinning for some reason. I think I need new clutches in it. You can plainly see it happen here.http://www.youtube.com/watch?v=cRxoXcBmkuo That's NOT me driving my car BTW. lol