eg9matt

i have a b series hydro diff sitting around but not sure what it is for and it does not have a ring gear and i want to get one for it so i can put togther my trans, the diff is stamped p80 what is this out of? now i know ls and b16 diffs use the same ring gear bolt pattern and the gsr is different but i dont know what this diff is so any help would be great its stamped p80 on the bottom side of it thanks for your help