Which Transfer Case

[rcbildr]

I'm working on my 85 4x4 3/4ton Suburban. The tranny (700R4) decided to go out and I am converting it to an SM-465. My plan (so far) is to use the stock transfer case. I have access to 2 Rockwell T221 transfer cases and I am trying to decide if I want to use them instead of the NP-208. I know the NP-205 is the best way to go, but I am using what I have. Would it be worth it to do the work now and use one of the T221's or maybe wait until the NP-208 fails and do the conversion then. I have a tranny set up for the rockwell and a tranny set up (kinda) for the NP-208. I have a new coupler -sleeve and all (I think) I need to do to use the Rockwell is to have new drivelines made.

I'm thinking about waiting for the NP-208 to fail, but the SM-465 is a heavy transmission....know what I mean. Any help will be greatly appreciated. Thanks!!!