Is an 8 1/4", 2.45:1 diff housing exclusive?

8 1/4 came from the factory behind 400-2 barrel Cordobas.

If you've ever tried to move one, the 8.25 weighs a LOT less than the 8.75.

In a street car with a moderate engine, that's less weight to pull around.

I wonder how an 8.25 stacks up against a 10 bolt gm axle?