I drove 2 LPG vehicles extensively, one a 6 cyl Chevy pick up, and the other was a 305-powered Chevy van.
They both ran flawlessly on propane, even in winter. True, they need a block heater if you expect them to start in sub-25 deg F weather, but are great once going.
Propane is extremely clean-burning. Engine oil stays much cleaner, for longer.
Propane has about one-third fewer BTU's than gasoline, so power is somewhat dinimished. But you can boost the compression ratio for greater thermodynamic efficiency. Propane is more resistant to pre-ignition than gasoline.
Propane fuel economy is somewhat lower, again, by about one-third, so it only makes sense of the local price of propane is significantly less than gasoline.
Propane fuel tanks are bulkier and heavier than gasoline. Space considerations usually means a reduction in range.
My pick up had a 15 gallon propane tank so it did not go too far on one fill up.
But my propane van had a massive 300 liter fuel tank which could carry 220 liters(59 gallons) of liquid propane (the rest was necessary vapor space.) My range was 700 miles or so....
My big concern is the flammability of propane in a serious collision. If I had crashed and the propane ignited, they would never have found my body.
