anyone know the differences in the frame on the 2wd trucks versus the 4wd trucks?
i know 2wd trucks had radius arm i-beam suspensions and the 4wd had the radius arm solid axle...will a 79 bronco d44 bolt under there?

Different crossmembers is one, and the 2wd lacked a transfer case. You would need a 4x4 crossmember and some brackets or crossember to mount the t-case.

From the firewall forward the frames are drastically different. Converting one of these from 2wd to 4wd is not a bolt on operation.

The 2wd frame rails are shaped differently than the 4wd. The front of the 4wd frame is boxed, the 2wd is not. The steering boxes are in different places. The front crossmember configurations are COMPLETELY different. And no, they can't be unbolted. Basically, IMO, the easiest way to make this swap happen would be to graft on the front of a 4wd frame. Otherwise you're looking at a fair amount of fab work.

you can convert a 2wd to a 4wd but the amount of work involve is hard to justify if the factory already made the frame best bet is find a 4wd frame and put your body on it

The Ford frame side rails are almost the same between 2wd and 4wd and you can put 4wd cross members in a 2wd frame as well as box the 2wd frame in the front its alot of work though and you need a 4wd frame as a doner . Im in the process of converting a 2wd 73 crewcab SB into a 4wd. One thing you need to keep in mind is that ford offered two frames in their F-250. A 73-771/2 4wd has a diffrent frame than the same year 2wd F-250. If your dealing with 1/2 ton stuff your in luck 73-79 1/2 tons all have the same side rails 2 or 4 wheel drive you still have to cut out the front 4wd cross member and side rail boxing though and reweld it all in the 2wd. Their was a write up on this very thing in 4wheeler mag about 10 years ago. Hope this helps.
Leadmic

THANKS!