[wilkin250r]

I've been thinking this same project. Of course, my TH350 and NP203 are in good running condition, so swapping them isn't as high a priority. But here are my thoughts and research:

First, I don't really care for all-wheel drive. It's an open differential between front and rear, so if any set of tires slip then all the power goes to them anyways. I don't believe it buys you anything substantial over 2wd.

I don't know about the NP203, but I know lots of people like the NP205, and they need to get creative to make it fit because of driveline clearance issues. The NP203 might be similar. Personally, I think you would be better off with a transfer case specifically designed to work with the 700R4 like the forementioned NP208 or NP241. If it's a money issue, I bet you could find a transfer case for possibly cheaper than an adapter for the NP203.

If the goal is milage, then I'd still advise you to dump the 203. Spinning all that front running gear is just eating gas. You want selectable hubs and the ability to just run 2wd.

If convience is your issue, I don't think there is anything devastating about running selectable hubs locked all the time. Sure, it will increase the wear and tear, but it can't be worse than an NP203 that is already running them locked all the time, right? I do this in the winter on my Ford pickup up and over mountain passes. Lock the front hubs, but keep the transfer case in 2wd. If I hit snow, put the transfer case in 4WD and I'm golden. I lock my hubs usually around early November, and unlock them around March.

Like I said, I'm in the same boat. I've got the same package, and I'm looking for the same change. I just don't see any major reason to keep that NP203. I researched it once, but I can't remember the reasons that led me to choose the 241 over the 208. But I DO remember they only had a speedometer cable for one year, and then they switched to electronic speedo. So I'm looking for a 700R4/NP241 combo from an 89 Blazer.