dana 18 in 70? you sure its not a dana20? if it is an 18 you will have to change the rearend as the diff will be offset to match up to the 18 t-case. if its a 20 then you will not have that problem. you will probably need to modify both driveshafts for length and u-joints as the 205 is a large case and probably has larger yokes than your jeep. you may have to modify the clutch linkage, what engine do you plan to use on this? a small block chev will bolt on but the stock engine will require an adapter of some sort. you would probably have an easier time putting in a t-18 from a stock jeep application, and after the cost of adapting it might come out cheaper as well.