I agree, a g-62 is perfect for the 47, that's what I fly in mine and it has a surplus of power here at 5,000 feet. One note of caution!
The IMAC flyers I have seen who build their first warbird have that LIGHT IS BETTER attitude. That usually stops on the first hard landing when they have to repair the landing gear mounts! A twenty four pound P-47 is not an IMAC plane and needs to be built more sturdy in order to withstand normal flying, Wing loading is much higher than the normal IMAC plane and you will never be able to get away with the things an IMAC plane does, especially on take off and landing. My suggestion is to build the plane per the plans, down to the last detail and you will have one great flying warbird.

Larry