help identify this 8.75

I figured out that 2070741 means 741 case and the span of years is 1964 to 72

I also found out that 1964 is the last year for bolt on axles meaning that this is for sure a 64 B-body rear based on the dimensions.

I think I will build this rear, now....can I swap out axles and brakes for a newer, non bolt on setup?