GM's 8.3L 'Mongoose' Diesel Tops Rivals in Power but Not Towing
General Motors has detailed the specs for its new 8.3-liter Duramax turbo-diesel V8, codenamed 'Mongoose,' which will power the 2027 Chevrolet Silverado HD and GMC Sierra HD. The engine produces 555 horsepower and 1,230 lb-ft of torque, surpassing Ford's 6.7-liter Power Stroke and RAM's 6.7-liter Cummins in raw output. Despite this power advantage, the Ford Super Duty retains the highest towing capacity at 40,000 pounds, while the GM trucks max out at 38,000 pounds with a gooseneck hitch. The new engine features compacted graphite iron blocks, a variable geometry turbocharger, and an Allison 10-speed transmission with advanced shift logic. GM unveiled this as part of a broader four-engine strategy for its 2027 light-duty lineup, which also includes two new naturally aspirated V8s and an upgraded 2.7-liter turbo-four.
