The company’s T800 and W900 ready-mix trucks are now available with the 2013 PACCAR MX-13 engine. The new 12.9-liter engine offers a range of 380 to 500 hp and 1450 to 1850 lb-ft of torque. The high-end horsepower and torque ratings are an increase over those previously offered for the 2010 PACCAR MX engine. Kenworth Truck Co.