Can anyone tell me if I can just change out the parts in this picture to give me more space for floats?
No you just need the right wheels with a proper offset to get the room What are the details of the truck someone may have a similar setup My tire guy is pretty good at figuring that out so your tire shop may be a good place to start
It's a '74 Dodge CM 900.
That an old 12,000 Rockwell Front? If it is the wheel bearings may not take too kindly to a heavy offset.
I would like to see a picture of the truck.