Adding to Jerry's comments:
25 years ago (maybe longer, memory not that good), the local LP companies used LP in their delivery trucks.
Maybe 25 or so years ago, even the LP companies quit trying to use LP, and went to gasoline and diesel powered trucks.
If it is not economical for the LP companies.........................................
I have personal experience with only one vehicle that was powered by LP.
In 1981, Dad purchased a new Winnebago with factory installed dual fuel (gasoline/LP) with a Chevrolet 454 engine.
Mileage (Dad kept complete records, no guessing):
Winnebago alone: gasoline - 9.3, LP about 4 (since how full you can fill an LP tank depends on temperature, difficult to really pin it down to the tenths)
Winebago pulling loaded 16 foot trailer - gasoline 6.3, LP - less than 2 on level ground (insufficient power to pull the trailer in the Missouri Ozarks).
I understand that an engine designed exclusively for LP (as Jerry discussed), will be some better than a dual fuel.
After a couple of years, Dad disconnected the system to save the $110. Missouri auxiliary tax (this in additional to the vehicle license) for using LP, only to find that the total system had to be removed, and the vehicle inspected by the Highway Patrol to remove the auxiliary tax. Dad spend several dollars (in the hundreds) to have the system removed, and put the entire system in recycling (polite word for junk!).
Jon
