[shall36]

Best case scenario is that the 5.7 is the same block with a different crank. IF that's the case, then options abound, starting with taking the 5.7 rotating assembly and dropping it in the 4.7 block. The 4.7 heads might not flow enough to handle the extra cubes. If that's the case, the biggest drawback would be running out of steam before red line. You might be able to port the 4.7 heads enough to get the flow needed for the extra cubes. You might also have to put in larger injectors.

If the blocks are the same, then a direct swap should be physically easy, but there might be some electronics and wiring that differs. I assume the 5.7 is vvti or vvt? And I would think doing a complete swap would work best with an ECU swap, but that might not be necessary...depends on how different the injectors are sized and whether or not timing curves differ much. But, I think if you swap the ECU, you're also in for a tranny swap? Or is there a separate controller for the trans?