Ford is going offer an optional equipment package for the 2014 model year F-150  3.7 liter  V-6 engine that will allow the truck to run on liquid propane gas or compressed natural gas.  This is a factory installed prep package includes pistons, rings, hardened valves and valve seats designed to run on either regular gasoline or natural gas using separate fuel systems. The cost will be $315.00 and will be available this fall.