What class are you trying to get into?
Here is a very basic list...
-Dana 80 rear/Detroit locker (wish I would have used one instead of my AAM 11. 5) if you want you could also upgrade the shafts.
-Dana 60 front, Try to get one without the CAD (2001-2002????) ARB locker
-Upgrade all the yokes and get custom 1480 rears built and 1410's
-Tcase (street truck???) if so a 241HD if you need a speedo, NP271 if not!!!
-5speed, have the fully splined shaft and the 1 3/8" main shaft put in.
-A good Dual Disk clutch meant for sled pulling
That is about it for drive train wise... as far as the engine goes, go nuts, ask around but what ever you do its not going to be cheap. Above was my own ideal drive line. . I jumped to the 6speed though and wish for pulling I would have kept 5 gears!!! oh well, live and learn!
RyanB