looking 4 a 70 or 40 series. how environmentally friendly are biodiesel landcruisers?

Wanted: I've just relocated to the US from Africa, where I had to sell my much beloved '70 series. I would like to buy the same (although it seems most of these models went to Canada) or else a '40 series in very good condition and under $10,000.
Question: does conversion to biodiesel make these old cruisers trully environmentally friendly or is it just like putting a filter on a cigarette (in effect, not doing very much)? How much does a conversion to biodiesel typically cost? Thanks in advance

 

[Eco 45]

If you can find a BJ42 or any of the Factory Built Diesel trucks it cost very little to run them on Biodiesel. The main thing to make sure when running Biodiesel is that all fuel lines and rubber coming into contact with the fuel be 100% synthetic--natural rubber will deteriorate when in contact with Biodiesel due to the alcohol used to make it. Running a truck on Biodiesel is much better for the environment than petroleum based diesel. Plus biodiesel lubricates the engine better and you wont be adding to the record profits all the big oil companies are taking it.

 

[Zimm]

its a LC. meet any environmentally friendly tractors lately?