Thinking About A Vegetable Oil Car

Lately I've been looking at old diesel cars on eBay and thinking of getting a cheap one to clean up and convert to veggie oil. Most of the nicer cars are the old Mercs and they can be a bit pricey, but it seems with fuel as high as it is all diesels are skyrocketing in price, especially VWs. I'd actually like to find a 5-speed diesel Chevette with A/C in decent, rust-free shape, but that's a needle in a very large haystack.

Has anyone here done this or thinking about doing this?

Are the Olds 4.3L diesels that bad?