Hi!
Let me tell you that it is possible! In fact, some folks have already done it.
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will get you started.There is a lot of info to be found there, and a lot of links to people whohave done it with everything from Diesel Chevettes (man, oh, man do I wantto find one! Anybody near Bloomington, IL have one?) to Suburbans with 6.2LDiesels.
The term for this is anything from from WVO (Waste Vegetable Oil) to SVO (unsure what that one stands for) to "Greasel"...not so much biodiesel...
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When I get some money saved up and start on the restoration of my 1984 GMC Sierra (6.2L Diesel) one of the fuel tanks will become a veggie oil tank and the truck will be converted so I can run both Diesel and veggie oil. Making people stop and look will be fun...as well telling them I'm driving on nothing except the time it took to prepare the truck and the oil...
William