The NP 203 transfer case with full-time 4x4 option (Crome caps on the front hubs) was very common. I have one - a '77. Up to you if you want to convert it. I've never had a problem with my full-time 4x4, but if you do any amount oh highway driving with it (65-70 mph sustained) you may want to think about it. NP-205 tcase is the best.
Off Road design's NP 205/203 doubler is the best if you can swing it:
http://www.offroaddesign.com/catalog...ck%20facts.htm
You will need some serious mods like drive shaft and support cross-mambers.
These doublers are radical in my opinion. If I had the bucks I'd do it in a heartbeat!
As far as the pinion angle lift question, opinions vary, but I belive 4" lift is the highest you can go without serious problems or mods. You may need a longer rear axle though if the spines stick out too far. You car re-position (re-weld) the axle perches or get some 4-degree shims. Rear shackle flip is the best way to go unless you go with lift spings in the rear - best by far. If you plan on doing any serious muddin or off roading I woud not reccomend blocks. You will have problems with axle wrap. What ever you do don't let some fool tell you it's alright to put block up front! You could end up in a world 'o hurt.
Rear blocks are not hard to install. but you will need longer u-bolts if you decide to go that way. Get cast iron blocks not the cheap auto part aluminum blocks those will shatter if you go off-road with 'em.
Rear window's a *****, no way around it. If your lucky it may just be a fuse or bad wiring to the window motor. You could also loosen the mounts and work the mechanism to closed and bolt it back up. If not get one from a junk yard ( roll the dice to see if you get a working one) or buy one from LMC truck:
http://www.lmctruck.com. You should also get a Classic Industries catalog. What you don't find in one you may find in the other.
You will also need a brake-line extension kit. one for each front disk and one for the rear axle. Your steering will also have to be heightened to handle the 4" lift. A raised steering arm or a lowered pitman arm is a cheap fix but your turning radious will suck ( especially turning to the right) A cross-ver steering system mod is the best way to go but it's involved and costs some bucks. You will have to replace the passenger side front knuckle to do this. Don't get the cheap weld-on fix or you may lose your steering when you need it most.
Let me know if you need any more info. I can help you avoid the f***k ups
I made restoring mine, and also the expense.