In my '67 elco I unbolted the panel at the front of the bed and used the area underneath to mount the battery and NOS bottle. I still had room for a 4way, jack and jumper cables. The tailgate is also hollow and I used this space to mount about 100 pounds of ballast. It made the tailgate hard to open but gave me excellent traction. I believe most elco's have this feature. Have fun!