Any differential from any 8 3/4 will work in any other housing, as long as you use the bearings that match. So a Detroit Locker that fits a 742 will fit a 741 will fit a 489 will fit a 657, etc.
The major difference between these different housings is the configuration of the pinion and bearings.
www.doctordiff is a Board member who does this for a living. Ask him.

R.