For my mounting bolt under the tank, I took a normal hex head bolt and headed to the grinder. I ground the head of the bolt down to about half of the original thickness. For spacers, I used an old heavy, rubber mud flap off of a dump truck and cut it into 2" strips as shown on Bob Westerman's 3A site. I think the mud flap even had the famous naked lady outline on it....

However, i had my tub on and off so many times I think I ended up leaving that bolt out for the final install. My jeep is primarly for show and paved roads and I didn't think the tub was going to fly off without that bolt in there. Plus, I had a nagging feeling in my mind that my "Bubba bolt" would work loose and end up rubbing a hole in my fuel tank. Bad enough I'm sitting on top of 10 gallons of flammable liquid in a 60 year old tank.....I didn't want to tempt fate even more.