Stopping to refuel a large sport truck can be a hassle, especially when you are towing a long trailer or car hauler. Even with an efficient diesel powerplant between the framerails, today's trucks just don't offer the fuel capacity to go more than 500 miles on a tank of fuel, and that is a real hindrance when you're eastbound and down, loaded up and truckin'. The solution is simple: Install an auxiliary fuel tank in the bed of your truck. But, what if you just can't give up that precious cargo space within the bed? What do you do then? You call the guys at Transfer Flow and order up one of the factory replacement tanks.

The owner of this GMC Sierra Crew Cab dualie regularly hauls a 38-foot race trailer with an NHRA A-fuel dragster inside and all of the pit supplies needed to go racing. Although his truck touts a stout Duramax diesel engine with enough grunt to pull the trailer, towing from California to far-off racing destinations meant making a lot of necessary stops for fuel, which wasted precious time. We outfitted his dualie with a new tank from Transfer Flow, increasing his truck's fuel capacity from 33 to 56 gallons, in a matter of hours. After the install, he was able to drive more than 800 miles on a single tank of fuel. Now that's a long haul. Transfer Flow offers tanks for several makes and models of sport trucks with both gas and diesel engines. Here's how the installation went down.