Mounting a Painted Body
If you’re starting off with a body that has already been painted, mounting it will require a different technique. Start with the same steps as mentioned in this article, but when it comes to actually mounting the body, you’ll want to first place a small dab of grease on the top of the body posts. Hold the body above the chassis and align it the best you can from front to back and left to right. Once you have the positon right, lower it down on to the body posts. When you pull it back off make sure you lift straight up so you don’t smudge the grease. The dots left by the grease will show you where to ream your holes.
This way of mounting is slightly harder, because you have to make sure you nail the alignment before you touch the body to the posts. The good news is that you can check the locations of the grease points and adjust if necessary before reaming your holes. The side-to-side spacing is easier to figure out then the front-to-back because you can simply measure off of the lines of the body to get it right. You can check the front-to-back spacing by flipping the body upside down, holding it against the side of the truck, and lining up the body posts by eye.