Bypass the fuel pump? Do you mean the lift pump or injection pump? You will certainly not bypass the IP. You could bypass the lift pump and use an electric one, but I don't think the lift pump is the problem. As far as what is the best engine for WVO, I suggest you get on the WVO forums and ask there. My understanding is that there are two important variables: Injection pump and injection type. So indirect injection is supposed to be best, and the Bosch inline pumps are the best. I don't know which engine combines both of those features. The 7.3 is IDI, but rotary. The International DT360 & DT466, and Cummins 5.9 all have the Bosch inline pump, but are direct injection. I have the DT466 and plan to do a WVO conversion on it. I think the injection pump itself is probably more important than the injection type (IDI vs DI). Most, if not all modern diesel engines are now DI, and people convert them all the time. The mid-1980s model Mercedes has the best engine to convert with both IDI and the Bosch pump, and mine has been happily running WVO for 3 years now... but that doesn't help you with your bus decision.