Murph,
I think you may have missed the typo in the add. The thread was more of a humerous spoof.
To answer your question, sorry I cant help. There have been several folks here talking about biodiesel in the past. You may want to post your question seperatly. I do know that current bio has a tendancy to thicken and oxidize your motor oil quicker. If your injecors require oil to fire, this can be a very bad thing. Bio will also strip the fuel tank liner in some trucks, causing premature clogged fuel filters and injector failures. For a tractor, it may be just fine, I'm waiting for the technology to advance before buying into it myself.