Outer Limits 4x4 Board

I have a shorty 40 with a nice fresh warm 253. Its running a 4 speed manual has front and rear air lockers and 35" muddies. The transfer case has just s#!t itself and I was thinking now is as good a time as any to do an upgrade.

What gearbox/transfer case should I use and what mods are required to make them fit, keeping in mid that it WILL cop an absolute flogging (its my toy, thats what its for) and I want to do it right the first time.
Are later 5 speeds any stronger as overdrive would be an advantage, or should i go auto (T400 for strength or T700 for o'drive maybe).
Should I just spend the extra $$$ on the original box & transfer and have them modified for strength, if so what mods will be required to make it practically bulletproof.

I dont mind spending the ca$h but I sure as hell dont want to spend it twice!!!

Buy a bell housing off dellow and fit a a440 and split type transfer out of a 60

im currently running the 4-speed manual with the original 1 piece trasnfer case and i havent had any problems.... even though i was told the 1-piece transfer were prone to cracking

however im upgrading to the split case out of a 45 or 47 series
(not sure - its basically the split case form a 60 series but it still has the drum handbrake at the back!!)
only because im goin dual transfer cases and there more options available for the plit case liek dual sticks and that....

whatever you do dont go for the TH700... i know its 4-speed which is handy but they r weak as shit!!! and if your ganna abuse your 40 like i do it WILL let you down.... you can beef up the internals and make it strong but you mise well build a killer TH400 and youll have change...

Put an Orion in there..

Thanx guys, at this stage I am leaning towards a 5 speed as all the info I am getting tells me they are pretty strong and I would really like the overdrive as it revs a bit hard at 100 in 4th. Am going to get it checked out and the transfer case modified before it goes in. Does anybody have or know of a suitable 5 speed box for sale, what should I buy....does a 60 series bolt strait into a 40, if not what will???

The transfer cases from 4-5 speed boxs are interchangable as such , I have mated a 4 speed transfer to a 5 speed before,
note a few shafts in the 4 speeds are skinnier than the same ones from the later 5 speeds like the 75 series ones