[Ryan]

I can tell you Ford Australia's LPG straight six isn't a conversion of a petrol engine but a dedicated six cylinder with unique conrods, head, manifold and the list goes on. We've been building them since the AU Falcon and at peak demand were building over 120 ( mixed in with our standard and turbo ) out of 450 engines a day.
A couple of years back we were just a weekend away from putting the gas engine into our Territory SUV but the idea was canned from higher up.
It's just a pity that the "Gurus" in Marketing don't promote it well enough so that the wider public see the benefits. Most people are not aware we even make it. We don't all need the be running to 4 cylinder cars.
Oh well, we are still making them daily and they still make up a great deal of our production. Unfortunately our production will fall soon to just 255 engines a day as the public move away from "scary" large sixes.

On a side note I just got a gas conversion done just last week. After the government rebate I'll only be out of pocket $800. Which will be made back soon enough through the cheaper price of LPG at the pump.