Google....
But you can remove your existing case with the ring gear, put the new ring gear on the limited slip and re-install.
The most difficult aspect of gears is setting pinion depth. This is not touched with just a case swap. You must match backlash and preload on the bearings to what is there now, but that is not hard. But entire books are written on this subject. You either need new bearings on the posi unit or pull and reuse yours. Once again, some special tools involved.
Google and read how to do this. Better yet, buy the book.
https://www.amazon.com/Chevy-Differe...al+repair+book
SO MUCH easier than when I had to figure it out in the late 80's.