This months Evans Tuning video tech article shows how to install a limited slip differential into a b-series transmission. The video is very indepth with three seperate break downs of the installation. The only step that was not shown is checking the side to side play after the differential was installed. This needs to be checked, although 99% of the time if the same style differential bearings are used, the clearance is within factory tolerances.
Link 2 evans-tuning (vids) http://www.evans-tuning.com/videotech_differential_swap.html