ATP designs
Behind Cab Frame Boxing Plates
These frame boxing plates are designed to fit in the section of frame just rearward of the back of the cab. They mount behind the rear cab mounts crossmember area. They are designed for 67-79 F100 frames but will work with some modifying on most all of the F100 frames. We have used these plates for just boxing the inside of the frame and also used them for both the inside and outside on long bed to short bed frame conversion as well for extra strength at the cut line of the conversion.
NOTE: If you use these on the inside of the frame be sure to either modify them so the front bed bolts can be accessed or weld in captive nuts so covering the area where the bed bolt nuts go is not an issue.
(1) order of Boxing Plates will get you (2) total plates. These are made from 1/4" mild steel. It is recommended to fully clean all the mill-scale off of the plates where you plan to weld.
You can see how we used these in our F100 Short Bed Conversion Pt.1 YouTube video.