If you remove the spare tire mount assembly from the rear frame portion, you can put a rear tank from a mid 90's ford f series in its place. If you use the 15 gallon or so you can use the factory skid and its flush with the bottom of the frame rails. Or put a 40 gallon bronco tank in and loose departure angle. Filler has to be figured out, I ran mine up through floor and out under the left rear tail light. No not a bolt in but cheap and effective.