I'll also ask what gears are in the axles?
The 302/C4 from a Bronco will be a really good fit into another Bronco. There is some welding needed to change the engine perches on the frame and some work getting a bigger radiator fitted in the core support. Any of the Bronco venders can help you out with those items.
You should be able to get the C4 and transfer case rebuilt for under a grand. Neither are complex and parts exist. Do not let the rebuilder talk you into a "shift kit", the Bronco already had a factory one in it. Putting a rebuilder shift kit in makes it too aggressive.
The 3-speed on the column can be fun. My favorite way of driving a 3-speed. The bad part, you are driving a 3-speed. From the sounds of what you want to do that shouldn't be an issue. But the 3-speed you have now is not the one to use with a V8. The length and gearing are different on the V8 version. Good thing is the V8 3-speed is not in high demand and they made a ton of them. Getting one usually isn't that hard. IF you fill out your profile someone near by might have one they will give you or sell real cheap. The shift rods for the V8 are different than the I6 as well, has to do with the different transmission length. The good part is the transfer case is in the same place so the driveshafts stay the same.
