you can look at it this way, a dana 60 will still be there ,long after many broken 8 3/4 rear ends. car weight has more to do with life of the rear end.
some super comp dragsters use 8 3/4 ,but has no weight. so it lives. a passenger type car will be a lot harder on it. I use to run 8 3/4 rear ends. broke a few of them. went to a dana 60, in a 3400 # clutch car, has been in use since 1992, 16 years # 100 + runs per year. if you want a light weight dana 60 housing, look under any 67 to 72 1/2 ford pickups. they had passenger car ends and axles in them, plus, were 30 spline like a 8 3/4 axle.
weight difference, 32 #.