There is one running around here that I see from time to time. I thought I had some pictures of it, but I can't find them. Its a long-wheel-base GMC 1/2-ton.
It appears to have 70's 1/2-ton four-wheel-drive axles using the stock springs. It has a V-8 and automatic, but that part isn't really your challenge.
Find axles that are not too wide, and realize that you are going to have to lift the truck up to fit the front axle underneath.
Find a 4-speed or 5-speed with transfer case, married or divorced, that are compatible, and from a Chevy or GMC, and then mount the 4-speed to your existing bellhousing, and add a crossmember to support the transfer case.
Then have drive shafts built.
Over simplified maybe, but unless you are going to go with a different frame with independent front suspension, you are going to need to raise the truck up. Going IFS four-wheel probably means a frame swap. Keeping the 235 either means using an adapter to put an automatic behind the 235, or the GM manuals that will fit your existing bellhousing.
I wish you were closer to me, this is a project I'd enjoy watching.
If I were doing this I'd try it different. I'd swap to a four-wheel-drive S-10 frame because it can allow keeping a stock ride height. Mounting a 235 in that frame might be a challenge...
