My workplace makes the "biodiesel" and sells it to employees at cost, for about 1.50/gal. We recieve used fryolator oil from local diners and cook it up with menthanol and lye. It works great, cleans out the whole engine and the only thing you have to do is change the fuel filter right after the first tankful, watch your fuel lines for potential deterioration (if your diesel is pre 83, when volvo supposedly used a natural rubber gasket which falls apart due to the methanol). Oh and it gels up the moment it gets cold, so you have to switch back to normal diesel or a mixture for the winter.

I'll try to get my hands on a floor pan. Now if I can just teach myself how to weld...

Thanks much for the encouragment,

Ben