You can build a diesel engine... Kind of

[Xaleros]

So to everyone who can't wait for a diesel engine, I managed to build a 5.9L I6 with almost exactly the same stats as a 5.9 Cummins, including max RPM, torque, and HP. My point being if you're creative you can essentially build a diesel engine right now. It won't -technically- be a diesel engine since it runs on gas, but if you try you can atleast build an engine with near identical stats.

[HorseMeat]

How's the fuel economy?
I manage to make the 5.9 and 6.7 but they required really hitest fuel, and were very thirsty.
Very undiesely

[Xaleros]

Well the engine itself has a 22% fuel efficiency value, but in the truck it gets 11.2 MPG. Though I'm guessing thats mostly due to my gearing (I tried to gear the transmission alot more like a 2nd gen cummins)

[Xaleros]

And as for the fuel I run it on, I only run it on the 90 octane premium. As well as my 5.9's specs being a bit higher than the real things specs.