Only real things left is the transmission and fuel system. I wonder if they have given any consideration for coming out with a transmission set up that would work with these crate engines. Schumacker now makes Hemi conversion engine mounts, so that is covered. The 5.7L is at 383 HP, the 5.4L at 485 HP. I think most of our cars would be fine with the 5.7L crate; it is at, or just past the power capability of the 8.25" with Suregrip. The 6.4L will require a 8 3/4" or stronger rear end.
Also, wonder what each of these crate engines goes for?