if the box is cut off with a stub hanging out you may be able to use it still. you need enough room to get a flat spot ground in to the input shaft to hold the universal joint. before you do that though, make sure to check the box, it could be worn out. not much to them if you wanna pull it apart for a look see. check here for more info
http://chevy.oldcarmanualproject.com...esto/56134.htm