Ford running out of diesel engines

Well there is more than going up a hill with a load and a diesel, although they do that easily. With a diesel exhaust brake they come down a hill better than any gasser will do in tow/haul and engine compression. Also to build a gas engine that approaches the reliability of a diesel is going to close that price difference somewhat. And the gasser is going require expensive smog control features. The advent of the V10's was for smaller displacement per cylinder to help control smog.