Used propane systems can be had for as little as $75 USD. That's what I paid for mine. I am installing it on a Cad 472BB so I am not concerned with the guestimated 10% power loss. I spent $250 for (2)10 gallon (43.5 LBS.) forklift tanks and $60 for #6 steel braided high pressure hose. $415 bucks total. Not to shabby if you ask me.
I have a damn near fail proof fuel injected motor with only one electric component to wear out. That part is an elec. over vacuum vapor lock that turns the fuel on/off in relationship to the ignition key switch. I actually have 2 in my system just in case. Propane is heavier than air so it will settle in the bottom of your engine if it leaks and once the fire is lit, KABOOM!
In Texas, you do not pay tax on propane at the pump. You go to the License and Registration office and tell them the amount of miles you drive per year. They take that figure and determine the amount of propane you will use and tax you there for that amount. In turn you get a window sticker that allows you to buy the fuel at a 0% tax rate. This sticker is required if you run the vehicle on the street. Get caught without the tax decal while running propane and you will be paying a very large fine.
As for the octane rating of propane, it has been determined to have a research value of 110 octane. At a refueling station it will be about 103 octane. Check out the write up on pirate here:
http://www.pirate4x4.com/tech/propane/index.html
Also note that with a cleaner burning engine your oil change intervals will be much higher. Of coarse if you don't do oil analysis on your used oil, you won't realize your true mileage potential between changes. But just for an example, my `03 F150's (government work vehicle on propane) oil is golden, like it was straight out of the bottle, with oil change intervals of 7500 miles. This is the cheapest 10W-30 oil that money can buy too. Just think of how many miles it could go between changes with synthetic oil.
