The Paccar MX-11 is a small block engine — lighter than the MX-13, with a lower GVW profile that translates directly to better payload efficiency on California’s weight-regulated roads and bridges. For agricultural hauling where you’re moving loads of produce, feed, or equipment across the state, that matters. You get 430 horsepower and solid torque delivery through an automated 12-speed that keeps your drivers productive and your fuel costs down on long runs between the field and the distribution point.

The 579 is also Peterbilt’s aerodynamic flagship. On highway miles — which is most of what California ag hauling looks like — the fuel savings add up fast compared to a conventional cab.