203/205/208 t-case mumbo jumbo

[tomtuna1978]

ok so ive got a 79 k10 short bed fleet side with the 350/th350/np203 gear(dont know the rear diff 12 bolt and front diff 10 bolt gears yet). The 203 case started leaking and the rear drive bearings went out a wile ago(truck has been sitting for 3 months). so ... ive been doing a lot of reserch on these transfercases and transmissions and junk, searched until my eyes were blurry and then surched some more ! from my reserch i now understand(correct me if im wrong !) that the np203 case is pretty much only good to make a doubbler with, the np205 is THE ! good case to get, and the np208 is a decent aluminum one that will take some abuse. NOW ... i have got a 700r4 trans out of a 84 van(2wd) for free a few weeks ago(was told it was rebuilt like 5k mi. ago, but would go threw it anyways to make shure). and would like to use it for the od,as the th350 is spinning the engine at like 4000 rpm at like 65 mph now. im only going to use this truck as a fun beater/light towing/and id like it to be as reliable as i can get.here is my questions ..... how much work is it to do the doubbler with the 700 trans(i can get a 205 for 350$), do i need to get new drive shafts and re mount the trans crossmember,and how heavy will that be ?(that 203 was heavy as hell !!!) if i can get the 208 case(havent even tried to find one of those yet), will it mate up to the 2wd 700r4 trans? and what kind of trans crossmember/driveshaft mods will i be doing? and what do you guys think this will cost me? and what would you do ? should i just rebuild the 203? and live with the rest of it ? i dont want to spend a lot of money on it rite now ! but i know i got to spend somthing ! any help would be aprishiated ! sorry for the long post !!! and i think i did as much reserch as i could ! if you guys got any more info sights or threads for me, let me have it ! thanks guys !!!!!!