Dang I though the 80 was strong?

It is going forward.  As long as you never have to back up under load or pull someone back it's very tough.  I blew a cryoed Precision Gear 4.88 ring gear on the front of my 80 going forward even!  I will do the Diamond/High 9 in my 80 soon as I like to play with out worry of POP!  The rear 80 diff is a beast!  The only real weak link in the rear is the e-locker.  New parts are nearly unobtanium and if you put a twist on the long splined short side it is a mutha to get out!  I'm running a Detroit with short splined Poly axles in the 80 rear on my FJ-40.