The photos below this may be vary but just to let you to compare Milennium Force vs Leviathan. The left photo is Millennium Force and the right photo is Leviathan. You will notice the bus on left photo compare to trucks or cars on right photo.
Seem that Leviathan is on the ground above the parking lots and my guess it will be approx 10 feet. So the drop height will be approx 316 feet. See the photo.