I bought what I thought was a GN rear for my 79 malibu.I took out the 7.5 and bought non-adjutable uppers and lowers.When I put in the GN rear the uppers seem to be farther apart and the rear wont fit.Im wondering if it is a Chevelle rear and I need the offset uppers.The numbers off the rear are 61JG067 on the Tubes and 14075742 on the Housing.can someone HELP me.