ive posted this many times before, and will again- in highschool i put a blown small block into a 83 4wd, the owner repeadedly did 4wd 5000 rpm launches for weeks untill he blew the rear end, so we put in a 9 inch...to this day (many many year later) he still has the same w56 and gear drive case, no mods. is he lucky? maybe...but i doubt it.
horse power? i dunno, over 500 at the crank