Adjust the Body Mounts
Place the body over the mounts, and adjust the front and rear mounts as necessary to get the body to sit level. If the body is sitting at an angle it can throw off the location of the mounting holes. At this stage it’s okay if the body is sitting too high because we are just trying to level it; you will lower it to the correct height later.
Adjust the body mounts so that the body sits level on the chassis before marking the post hole locations. If you leave it sitting at an angle like this, you may have post holes that are slightly off.