Hey Elliot - I see your old bus is painted. Time to update your thread!
Regarding WVO - some diesels like it better than others. You should seek out another forum dedicated to WVO issues, and I think you will get a better response. Certainly older engines are more suitable than newer ones. But there are various factors related to injection type (direct, indirect, common rail, etc.), and (manual vs electronic) and type of injection pump (inline vs. rotary), that will determine how compatible an engine is with WVO.