The 229 is a really nice choice because it is externally identical to the stock Eagle transfer case except for the extra low range lever parts. It is possible to take a bad 229 and a good Eagle 129 and mix them together. The low range lever is also compatible and easily installed. The bad thing is that the viscous coupling in that family of transfer cases (119,129,128,219,229) simply doesn't work very well in comparison to the newer options.
I think you said you have a four speed. The stock stickshift transmissions are all compatible with a NP242.
The NP242 is much more common and easily found, mostly in Jeep Grand Cherokees. In most cases you can find ones on Craigslist already pulled and ready to pick up. There is a number of lever solutions, although none of them are as simple as the 229. The NP242 has an open differential AWD option identical in performance to the NP128 found in all 1986 Eagles. It then also has a "part-time" mode with the yokes fully locked. That is really nice in very slow, very slippery conditions like on beach. There are also NP249s and NP247s as options.
The military HUMVEEs use a GM input version of the NP242.