Available as a Class 7 or Class 8 model, the new MHD 4×2 from Mack Trucks is available now for order. The Mack Granite Medium Heavy Duty (MHD) model is the latest version of the Granite MHD launched in 2011. A Cummins ISL9 345 HP engine rated at 1,150 lb./ft. of torque powers the MHD 4×2. The truck also features a galvanized steel cab, the Mack Cornerstone chassis built of high-strength steel alloy offered in four frame rail thicknesses ranging from 7 mm to 11.1 mm, and a clean back-of-cab design to accommodate a variety of body options, including those required for utility, dump and municipal applications.