That's not possible. If the 55-inch 4K panel only gives 540p per eye, that makes it 1080p, which isn't enough to fill the screen. It all depends on whether the source is 4K or not, be it a 55-inch or a 65-inch panel.
If the source is 1080p, then its first upscaled to 4K, and then split in two for passive 3D. This is what my understanding is.