I came across a used GMC C-6500 that is propaned powered, and since I know nothing about propane I thought I would see what you guys thought about it. I am almost willing to bet it is a used Schwan Frozen Food delivery truck because of the color of the cab and I've heard a rumor that their trucks are all propane powered. It's sounds like a nice deal other than the fact of it being a inconvenience to fill up.

I checked into propane for my pickup several years ago. At that time I was told fuel mileage and power would drop a little, but engine life would be greatly increased.

Power wise do you think it is the same as a gas or diesel motor?

you will have less power with the pane. but you may not notice. you will notice the fuel economy drop. i dont remember the % drop but its enough you will be disapointed. unless you have a source for cheap bulk propane and have a tank you can store it in an pump it yourself. the engine in theory should last longer because the propane is already a vapor when its induced into the intake. gasoline or diesel is not and can wash the cylinder walls clean of oil. also the exhaust smells bad. mrcaptin or whatever it is that they add to the propane to make it smell bad comes out the exhaust.

also cold weather starts can be a problem. i know this because i worked (only 5 months)for a propane company and delivered bulk propane with a c7500 chevy with the 8.1. and every thing they had ran on propane. they had a 2wd excab chevy with a 350 a 97 i think. when i drove that i would always top it off in the morning and refill when done. would always be 12mpg or less!

they use a vaporizer the workes of the heater hose to turn the liquid into a gas before the intake so on cold mornings they will not start unless you have a coolant heater you can plug in.

hope this helps.

You lose 20-30% of power. My dad owned a 94 3/4ton suburban, 350 CID propane. Gutless and Averaged 10-13 MPG. But back then he could get propane for 3 cents a litre during the propane price wars.

Thanks for all the info guys!

If i recall when i checked into it the power drop was only like 10% because the "octane" level of propane will vary between 100-115. All the schwan trucks here are propane as are all propane delivery trucks. You will find that most of the guys who drive these trucks and or work on them that are into hotrodding will have their vehicles converted to propane. You can also buy the kit to convert your carb. engine through ACME. Yes, i said ACME, the kit cost around $900 and you use the base plate off a holley 4 barrel carb. This will give you the same performance as fuel injection, alot fewer emissions than gas and less carbon contamination inside the engine oil.

The power loss should only be 4%. This is because the fuel goes in as a gas and displaces some oxygen. Usually it isn't noticable. If you lose more than that, something isn't working right. If you build the engine for lp, meaning higher compression to take advantage of the higher octane rating, you will get more power than low compression on gasoline. I have a 454 w/10:1 compression that makes great power on lp. It has to have 93 octane gasoline at minimum however.