These are made from .090″ 5052-H32 Aluminum.
Use the construction lines on the drawing to note where the sides and back roll up. Roll up the edges with a 2″ radius; roll the back up with a 3″ radius to about 60degrees. After you roll the back up, the sides should overlap; rivet them together.
You’re on your own with mounting them into whatever deathtrap /hot rod you’re building.
Contact me if you want the SolidWorks .sldprt