Moving up in the PACCAR line takes us to the MX-11, which is used in Peterbilt model 567 and 579 trucks. This 10.8-liter engine can put out as much as 430 horsepower and 1,650 pound-feet of torque.

This Cummins-powered Peterbilt Class 8 tractor-trailer demonstration semitruck recently achieved 10.7 mpg during testing. While that’s not in the range of a Prius, remember this behemoth hauls ...

Yellow Corp. is refreshing its fleet with an order of 1,222 Peterbilt Model 579 trucks, the largest single-year order Peterbilt has ever had of trucks spec’ed exclusively with a Paccar powertrain.