in '79 model K5 blazers, are the 4x4 and the 4x2 differentials the same width? And are they both narrower than a 70s or 80s pickup would be? I am trying to verify what I have been told. A friend said he used a '76 model K5 4x4 differential in his '49 First series PU. I want to do the same thing for my '55 first series PU. Apparently the K5 's are only an inch or so wider than the original PU differentials. Any info would be appreciated!