I searched for a long time for a carrier to replace the 4.57 gears in my 48-3/4 ton. The prime donar is the 67 to 72 3/4 ton trucks. I found a bunch of 4.57 geared trucks before I found a 4.10 carrier. As far as I know, those were the only gears available for those years. There were aftermarket gears available for the 67 - 72 carrier that would get you 3.78's, but those were not factory and had to be installed by an expert.
Ralph
