This link discusses the problem for ambulance manufacturers http://www.jems.com/emsinsider/25-3/280853/ but I also read another article where Ford is still able to use the 6.0 in 2007 vans due to some type of emissions credit . The supply of 6.0's is limited then the E series will only be available with gas engines . http://media.ford.com/newsroom/feature_display.cfm?release=24890 . The absence of a diesel is conspicuous .