Moser Engineering Rear Ends?

went back to an old post to find > Dana vs 8 3/4
both are 53" F-F , weighed without brakes


Dana- 4.10 spool/ stamped cover = 97 lbs.
8 3/4 - 4.56 spool= 99 lbs.

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What is the reason for this since by all accounts everything associated with the 60 is heavier?
Even the tubes.