Where do I find a complete Gas to LP conversion kit for a 305c.i. w/ 4bbl carb?

I googled LPGas carburator, and came up with IMPCO Carburator at www.propanecarbs.com Try that.

Propane was a good idea back in the late70's and part of the 80's. The cost then was around 17 cents a gallon. I set up many systems on school buses cars, pick-ups, semi tractors and even a few farm tractors. JC Whitney may still carrie the set up you are looking for your truck. Keep in mind the cost will be very high and I can tell you now that whatever your mpg is with gasoline, subtract 30% for your 305 cid. In a nut shell, the 305 cid dumps it's mpg. A special fuel tank to comply with DOT is needed for propane and you do not want to be without it. The second unit I installed in 1977 caught a fire from a piece of wood in the road striking the fuel line. This 80 passenger bus was gone in 11 minutes. (just a little something for you to think about) And approve DOT tank is now law ($$) and you can easily guess why. Think it over. If you are getting 10 mpg now, plan on 7 mpg with propane.

Have you looked into ethanol?

Nobody sells it here yet. They are starting to build ethanol plants all over here but none at the pumps yet

5star is correct abpout the mileage on a STOCK small block Chevy however if you take advantage of propane's higher octane rating you can recover most of that loss. We ran our 350 SBC pickup on propane with 11.5 CR pistons and the mileage was always around 14-15 mpg around town which was within 1-2 mpg prior to the conversion. Power was down at RPM's > 3,000 because the propane carb was only a single throat unit. Of course with a high CR modification you lose the ability to run multiple fuels except straight alcohol which can be very economical at CR's of 13:1 or more.

I do not know what difference it will make but by accident I ended up with 350 heads on the 305 block, it has an edelbrock high performance intake and currently a 600 edelbrock 4bbl carb, when I replaced the heads I also replaced the camshaft with a mild lunati cam but I don't remember the numbers on it, it is a mild cam though.

Impco is a very good source, but I don't believe they provide the whole package to the public. They are a manufacturer, although when I was at their plant on a joint venture, I noticed they did alot of retrofits for Postal vehicles and also Chevy Cavaliers & 1/2 ton Trucks that were used as city vehicles. I doubt you will get the whole system for $200. I found a company out of Phoenix, AZ that sells complete kits for off-road use but I believe it ran over $1,000 and it wasn't approved for the street. It caters to Rock Crawlers, so you can eliminate the fuel delivery issues that carburated vehicles get when in extreme angles. Impco's stuff will probably be even more, because theirs is micro-controller based. Their is a slight difference in MPG, but than that is offset by fact that Propane is about 2/3 the cost of Unleaded.

Try converting to hydrogen.

I don't have a particular favorite alternative fuel. I just want the option of using another fuel while still being able to switch back to gasoline if I was on a trip and couldn't find the alternative.

I also have to be able to do this on a small budget. I am one income for a family of four and I could probably do the conversion for up to $1000 but could not afford much more to dump into it. Now once I try one and It is a proven deal for me I could upgrade then. This is why there are few doing the alternative fuels here in the U.S. Personally I would rather fly an ultralite to work and get rid of the traffic too but my employer wouldn't like me landing in the parking lot.

LP is already distributed well enough to give it a try, I have read that MPG is about the same as Gasoline but the fuel is cheaper. The cost of the tank is no big deal, I can get one free or cheap from my employer

Something that will really help me out is:

How many Lbs. of LP equals 1 gallon of gasoline or vice versa?

I once had a Chevette that I equipped with a water steam injector in the fuel line immediately after the carburetor. The water was sucked from a reservoir into a small chamber strapped to the engine exhaust pipe. The resultant steam mixed with vaporized gasoline from the carburetor. I used a water/alcohol mixture to increase my mileage about 10 percent. I probably could have used pure ethanol just as easily, but the water steam by itself results in a higher gas mileage. At that time, ethanol was much more expensive than gasoline so I abandoned the project after satisfying my scientific interest. This was a very low cost minimal modification that has been proven to work.

One technique that I haven't tried is to manually release propane into the air intake of my fuel injected engines. Perhaps it could be safely mixed at the air intake with oxygen from a controlled oxygen generator. If we are willing to go to that much trouble, we might just as well use the wind power from the moving vehicle to break apart water molecules into oxygen and hydrogen which can then be released into the air intake. It seems wasteful to me to break the water molecules apart and then to separate the hydrogen atoms into protons and electrons just to drive an electric motor. Whatever fuel we don't release into the air intake will have to be made up for by depressing the accellerator pedal to give the engine more gasoline. This is a true multi-fuel system that should cost much less than $200.

My driving habits with a 90 mpg motorcycle and a 14 mpg SUV results in a combined mpg of 50 miles per gallon. Nevertheless, I'm increasing my sunflower crop to three acres which should provide enough ethanol for two SUV's for a year of driving. Why are we still importing oil from overseas?

305's are dogs to begin with power wise. You are better off with the 350 heads in most cases, and the cam and intake upgrades will certainly help, but if its an LG4 casting on that block, run away. They are notoriously weak blocks and may not be able to handle the higher compression, especially at higher rpms. I drive heavy, propane fueled vehicles everyday (Zamboni's no less) and I can tell you from years of experience the following:

1) A canister of propane last about 5 hours of constant run time (20 ice makes) with a 4-cyl 1-bbl carbed volkswagon engine running at 2500 rpm. the canister is about 2.5' tall, and about a foot in diameter. To be fair though, a zamboni weighs alot more then any truck.

2) The engines need about 10 min to warm up before they will idle smoothly

3) the engines are very sensitive to loose throttle linkages, throttle plates, etc.

4) an oil pump which isnt supplying the correct amount of oil will lead to a piston flying through the block within seconds.

5) Invest in a good catalytic converter. Without one your emissions will contain ammonia and you'll probably fail inspection.

Now all that being said, there are kits out there to add propane injection to diesel powered applications much like nitrous is often added to gasoline systems, and they do plumb right into the air intake "snorkel" and are reported to add torque. I think bully dog sells them, or maybe banks power. I dont remember exactly, I saw it on an episode of Trucks.

Another possibility, not mentioned here, is to change the truck for something else, something that does more mpg and will have less of an impact on the stretched family budget hinted at. An increase of $1 per gal, the number of gal consumed per year and the number of miles per year can soon form a case to justify liquidating the Chevy and selecting something else. Then, that's economics, not engineering, sorry.