My 71 D300 is a 10 ft. flatbed truck, When I bought this truck the first time in 2003, it had been a dump truck, but was a cab and chassis when I bought it. It had an aux. tank on the driver side frame, but I removed it as it was in poor condition. So now as owner again of this truck, which apparently passed through several owner and 4k more miles in the approx. 15 year between my first and now second ownership, I want more fuel capacity. I have been hunting for the perfect tank for about the last year--since I bought the truck last year. I figured that a round, 33 gal. tank from an older Isuzu NPR would be perfect --15 inches diameter by 43 inches long They are hard to find in good condition, and good ones cost more than I wanted to pay. Finally, I saw one on CraigsList that was essentially new--it was a take off and sold with all brackets, etc and the price was VERY good. It will be mounted on the driver's side frame under the deck bed and fits perfectly between the exhaust stack and rear spring hanger, with inches to spare. I will get to it in the next few months or so --before Spring when the Dodge is removed from its Winter nap.