Alrighty ending the night with a dumb question to send off. If I was to make my 1993 Ford F-250 E40D Rwd 351W extended cab, longbed into a 4wd what would I need?
I know essentially that I would need to find a matching truck with matching specs but 4wd, it would need to be a 351W with the same body specs but 4wd right? I would need to take out the 4wd solid front axle, the e40d transfer case, both front and rear driveshafts (would the length be different or could I reuse the old one?) Would I need to replace the wiring harness? Would I need to transfer the ECU? Would there be any issues with the transmission cross member, and or would I have to replace it? If I do have to replace I understand that it is riveted in, I assume that I would need to bolt it down really snug? Would there be any incompatibility with my current rear end? (3.55) I assume that there would be rivets on the floor pan to pop out to place the 4wd stick?
Please let me know what I will need to do, and if there is something that needs to be added that I missed.

And anyone that says just buy a 4x4 truck that works will be ignored. This truck is my baby. Her engine needs rebuilt, currently running 95 psi average per each cylinder at 420ish thousand miles. She cranks first try. She has no rust on her, all the primer spots you see are where the previous owner tried prepping her for a paint job half done and where rust started to set in, I angle grinded the rust off and primed over it followed with a clear coat. I have owned her for around 30k miles now.

I thank anyone who can tackle my questions!

The photo is taken back in February 2021 during the freeze that hit us while I resided in Texas.

 

Yes you need another truck just like yours except 4wd. To do a swap like this almost the whole powertrain has to change.. everything except the engine and rear axle, so it might even be easier to swap your body onto a 4wd rolling chassis. Yes the trans has to change too.. you can't bolt a t-case on the rear of a 2wd trans, well you can but the whole thing has to be disassembled to change the output shaft, then once it's almost all back together instead of fitting the 2wd tail housing the t-case is bolted up. Or you find a 4wd trans and swap it in. So you need a small block E4OD truck with the same wheelbase to get the right driveshafts, and then you can decide what is the better way to tackle the project. The 4wd F250 and F350 also use leaf spring front suspension not coils like the 2wd, the F250 could have either a D44HD TTB or D50 TTB front axle while the F350 trucks will have a D60 solid axle. If you're feeling creative you could try installing a 4wd front axle with coil springs, it should ride better than the factory leaf setup.