Idea in progress- good or bad

[4x4_Welder]

Along with all the other stuff I wasted my money on yesterday, I picked up an NP203 case from a Ford. It's a divorced unit, has the 2.00:1 ratio, according to the tag. I know that using the front portion is a popular way to get lower gearing, but can it be made to bolt up to a D21? I'd like to keep the D21 case, since it's in good shape and is a fairly stout unit, but I can't live without low range. Even my Subaru has a low range (gonna have a second 4.0:1 low range soon).
I know anything is possible with a torch and welder, and I do tend to follow that theory, but figure I'd just see if anybody has any input before I go throwing money at stuff.

[xxxtina63]

I've never seen a NP203/D21 before, but that's not to say it can't be done. One option you have is to convert the NP203 to part time. A lot of places have an inexpensive conversion kit, but the best route is to use what I think is called a "shaft replacement" kit. This removes the full time feature and makes it like a part time t-case, kind of like the NP208. Supposedly, an added feature is that you can run in low range while in 2WD.

[4x4_Welder]

I'm thoroughly modifying an S code intake, drilling and welding in inserts, hogging out the top to two holes instead of four, running a megasquirt controller, and a DUI self-contained ignition system.
I'm trying to avoid the divorced route, I want to keep the carrier bearing where it's at because of the rear suspension system design. I really just need a holdover for the time being, eventually once I can afford it I am throwing in a Stak monster box 3-speed.

[averagef250]

Alot of work and custom machining$$$$. If you want to stay married case why start with the range box from a divorced 203? Those stak boxes are nuts.

[4x4_Welder]

I'm putting a Samauri t-case under it in the late summer, after I move. I am doing it a different way, making a new front crossmember to add the front diff with only 5" of lift, instead of the usual minimum of 6-7".
I have no fear of doing machine work, I can do a precise enough job to work as needed. If it gets too deep, I can always take stuff to the machine shop next to my work. Or, if it will be really expensive there, then I'll call up Grainger and get myself a milling machine for a little under $2k. I can write that off as a business expense, and the shop will need one anyways.