If it is the p-pump that is missing you will need to get a new one. That is what delivers the high pressure diesel to the injectors, it is all about pressure. The FASS or Airdog is what gets the fuel from the tank to the p-pump you would use one of those to replace the lift pump. The lift pump is like the type of pump from a pre-1960's motor. There are other options I have seen people use insted of the FASS and Airdogs that might save you a little money. I am running mine off the factory Ford Diesel set up until it can no longer keep up, then I will get an Aero pump and some filters and make my own set up.