GM Reveals Gen 6 LS V8 Power Numbers For 2027 Silverado And Sierra

If you needed any more proof that General Motors remains committed to the good old-fashioned pushrod V8, here it is. The General has released even more info on the truck versions of its sixth-generation LS, and it appears the company went bigger and better in every way.

Of course, bigger and better starts with the program’s iconic 350, 400, and 409 cubic-inch displacement figures. Better is certainly the fact that the mills will be assembled at both the company’s historic Flint, Michigan, and Tonawanda, New York, manufacturing facilities. And naturally, bigger power is in store, with the 5.7L being good for 402hp and 428 lb./ft. of torque, and the 6.6L clocking in at 481hp and 501 lb./ft. of torque. That officially makes the 6.6L L78 the most powerful naturally aspirated V8 in the light-duty truck segment.

Breaking Down The Bigger

The 5.7-liter L76 replaces the current 5.3-liter L84, while the L78 takes over for the 6.2-liter L87. Both engines retain GM’s traditional 4.40-inch bore spacing, which dates all the way back to Chevy’s original Gen I block introduced in 1955.

The company found additional displacement primarily by adding 6 mm of stroke compared to the outgoing LT engines. Engineers also increased compression, opened things up with larger throttle bodies, and developed new intake manifolds with tuned runners to max out additional airflow. For perspective, the outgoing 5.3-liter L84 produces 355 horsepower and 383 lb./ft. of torque, while the 6.2-liter L87 is rated at 420 horsepower and 460 lb./ft. In other words, these aren’t merely familiar engines wearing new badges.

But Wait, There’s More

The displacement correlations aren’t the only interesting part for LS nerds. Both truck engines use a new dual-fuel system that combines direct and port fuel injection. That gives GM more flexibility to optimize power, efficiency, and emissions depending on operating conditions. There’s also a redesigned lubrication system featuring a continuously variable oil pump, an engine-mounted oil cooler, and revised oil-feed locations intended to improve pressure consistency.

Before the new Silverado 1500 and Sierra 1500 reach dealerships, GM says its development teams expect to accumulate more than 1.5 million miles of real-world validation. The new V8s will be backed by a 10-speed automatic, and the 5.7-liter Silverado will offer as much as 13,700 pounds of towing capacity when properly equipped.

That’s all well and good, but as LSX readers, we’re already looking a little further down the road. GM has spent more than 70 years evolving Chevy’s iconic small-block. Now we’re getting factory 350 and 400 Gen 6 truck engines with dual injection, nearly 500 naturally aspirated horsepower, and familiar pushrod DNA. The trucks haven’t even hit dealerships yet, and we’re already wondering what happens when somebody stuffs an L78 into an old Camaro and starts getting rowdy!