oopp's sorry I guess I did'nt read it very well, Kwik is correct if you plan on running B-100 the pre 2003 7.3 liter is the way to go, 2000 or 2001 have what I belive to be the strongest bottom ends (wich is very important when running a potentialy higher energy content than petrol based fuel) I kmow many people are running these trucks on straight Bio & having excellent results. Just remember filtration, filtration & more filtration!