GM unveils 8.3L Duramax diesel for Silverado and Sierra HD

GM has built its largest-ever production pickup V8: an 8.3-liter Duramax "Mongoose" making 555 hp and 1,230 lb-ft. It debuts in the 2027 Chevy Silverado HD and GMC Sierra HD, with a max tow rating of 38,000 pounds.

• 555 hp and 1,230 lb-ft beat Ram and Ford diesel offerings
• Silverado 3500HD and Sierra 3500HD tow up to 38,000 pounds
• Compacted graphite iron block with fully forged internals
• Dual-stage air-to-water charge cooler and electric power steering