2wd - 4wd can be done. But it will cost some money.
theres 2 ways of doing this.
1. Go to a salvage yard and strip out all the front suspension, including the 8.8 Front diff and CV shafts. If you cant find this stuff used then you can buy it new.
2. T-case you will need one. I think our trucks use a Borg Warner
3. Front drive shaft
4. Make sure to take the hubs/ spingles from the parts truck
5. The front diff will need the same gear ratio to be functional
6. Im not sure if the T-case will bolt directly up to your 2wd transmission but it might.
7. the rear drive shaft will probably have to be shortened
8. you need either an electrical sending unit or manual shifter.
9. theres multiple wires and vacuum lines that you will need
SCRAPPIN THE IFS FOR A SFA
1. Locate either a D44, D50, or D60. Ford 9" Front will also work.
2. then decided how you want the suspension setup. Leaf springs, radius arms and coil springs, 4 link and coil overs. theres multiple options here
3. Decide on desired ride higth, you will need to add around 8" of lift to clear all the crossmembers.
4. If you cant do the welding yourself find a repected 4x4 shop to do it for you. Agains popular belief a good shop can make a bolt on conversion for an axle of your choice but it might be more expensive than just having them weld everything on. (thats what im doing)
5. You will still need a t-case, id go with a NP205 unless theres gonna be clearance issues.
6. there still will be wiring and such to deal with.
7. Decide what steering you would like to run, high steer, crossover steer, hydro assist.
I think a Solid axle swap like the second plan would be alot better than trying to convert to 4x4 and keep the IFS.