4WD conversion

The front suspension, whole front end needs replaced. Get a donor 4x4.

I will not say it is stupid but dang hope you got skills

Dumb, but interesting idea that will take many hours to accomplish. I would say "no way Jose'", don't even consider it. Repair what you have or get another truck.

A f350 motor being in it means nothing unless you made it diesel or swapped the old v10 in. A 5.4 is a 5.4, f150 or f350 doesn't matter. Converting the truck to 4x4 is one of those things that are "possible" but not practical. You would be better off fixing your trans, selling it, and buying a 4x4. You could probably put another transmission in that truck and still come out on top.

I paid $8k for the truck and still owe $6k on the loan plus the $4700 for the engine swap. I'm not getting rid of this thing after that much has been put in

Just buy a 4x4 and save your self a lot of expense and misery.