Ford has been talking bout building their own CNG truck quite a bit over the past year or so. Finally, the first CNG equipped F-150s direct from ford have begun rolling off the assembly line.
The trucks will come with a variety of upgrades to allow for duel fuel operation. Hardened valves, pistons and piston rings come standard. The truck will be a duel fuel vehicle. It is possible to run it as a pure CNG vehicle, but the original gasoline fuel system is still intact too. With both tanks full, you can drive a 750 miles before needing to stop.
As you might expect, these trucks are largely aimed at the fleet and business market. The markup on a dual fuel F-150 generally runs between $6000 to $9500 depending on tank size. The markup is considerable, but if you have easy access to inexpensive natural gas, the additional expense could very easily be worth it. It's also worth mentioning that several states offer rebates and incentives for natural gas equipped trucks.
Even if you're not that interested in one yourself, it's good to see Ford committing to alternative fuel sources. Now... How about that diesel?