Any year will be fine, just make sure to get the version that's set up for a 205 t-case as the output shaft and housing are not the same as 2wd or fulltime t-case models. The 400 is stonger, but not as common as the 350, and it doesn't have as low of a first gear as the 350.
You might consider the 700r4. It has an even lower first gear than the 350, plus overdrive. Advance Adapters makes an adapter to use it with a 205 t-case. Just something to consider. If you do go with the 700r4, get the late one (post '86), early models have weak pumps.
