AutoblogGreen has some more details on the new Duramax 4.5L diesel V8 that GM is working on. It sounds like the intent is to make this new engine able to fit in any of the existing GM models that have a gas small block V8. That would include the Chevy and GMC light duty trucks, as well as the Yukon and the Hummer H2. The downside is that it won’t be available until after 2009 so we’re stuck waiting until the 2010 model year (at the earliest) to get our hands on this new diesel.
PickupTruck.com has an article on the new 4.5L diesel V8 also and they reference an Automotive News article stating that the engine will get 30 mpg (7.8 L/100km) highway. That’s a pretty substantial improvement over the 22 mpg (10.7 L/100km) that the 5.3L V8 gets.