Advanced Fuel Dynamics ProFlex DXI Adaptive Flex Fuel System (5.3L)

This is a flex fuel conversion kit. It adds an ethanol content sensor to the fuel line and a controller that plugs into the factory harness, so the truck reads how much ethanol is in the tank and adjusts fueling on its own. That lets you run E85, gasoline, or any mix of the two.

why this one — No tune, no injector swap and no pump swap, and the module stays invisible to scan tools, so this is the simplest way onto E85. The retailer listing for this part claims 40 to 45 wheel horsepower on E85. The catch is obvious: you get nothing out of it unless E85 is actually sold where you live.