WARNING: This page is about a different car, the 2015 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Engine Cylinder Arrangement - 5.7L
Courtesy of CHRYSLER GROUP, LLC
The firing order for the 5.7L and 6.4L V-8 is 1-8-4-3-6-5-7-2.