GM V8 Engine Updates for the 2027 Silverado and Sierra Explained

GM’s V8 engine updates for the 2027 Chevrolet Silverado 1500 and GMC Sierra 1500 are substantial: the current 5.3-litre and 6.2-litre V8 options are being replaced by new sixth-generation Small Block 5.7-litre and 6.6-litre engines. The new 5.7L produces 402 horsepower and 428 lb-ft of torque, while the 6.6L is rated at 481 horsepower and 501 lb-ft. Both arrive with the next-generation light-duty trucks later this year.

New GM 5.7 engine specs: horsepower and torque

The new 5.7-litre V8 makes 402 horsepower and 428 lb-ft of torque. That is a meaningful step beyond the outgoing 5.3-litre V8 in the areas buyers tend to notice most: acceleration, load response, and pulling power at lower engine speeds.

GM says the 5.7L is part of its sixth-generation Small Block architecture and will be available at the launch of the next-generation Silverado 1500 and Sierra 1500. The automaker’s announcement of the new-generation Small Block V8s confirms that the engines will sit alongside the Enhanced TurboMax petrol engine and the available 3.0-litre Duramax turbo-diesel in a four-engine light-duty line-up.

New GM 6.6 engine specs

The larger 6.6-litre V8 is rated at 481 horsepower and 501 lb-ft of torque. Car and Driver’s report on GM’s released power figures says both new V8s will first be offered in the 2027 Silverado 1500 and Sierra 1500.

The 6.6L should be the choice for buyers who prioritise the strongest naturally aspirated V8 output in the new light-duty range. GM has not yet released every specification buyers may want, including pricing and detailed trim-by-trim availability, so it is too early to assume which engine will be standard or optional on every model.

Is GM getting rid of the 5.3L V8?

For the 2027 Silverado 1500 and Sierra 1500, yes: GM’s new 5.7L and 6.6L V8s replace the previous 5.3L and 6.2L V8 offerings. That does not mean the 5.3L has disappeared from every GM vehicle or application, but buyers considering the next-generation light-duty pickups should expect the new displacements instead.

The change is more than a simple increase in capacity. GM describes the engines as part of a new Small Block generation intended to improve capability and performance. V8 demand also remains significant in this segment: CNBC reported that GM said V8-equipped models accounted for 55% of Silverado sales and about 61% of Sierra 1500 sales this year.

Will the 2027 Silverado have AFM?

GM’s announcement and the supplied published specifications do not state whether the new 2027 Silverado or Sierra V8s will use Active Fuel Management (AFM), or identify a replacement cylinder-deactivation system. Buyers should not assume that the hardware or calibration will mirror the outgoing 5.3L and 6.2L engines until GM publishes full technical specifications.

That distinction matters because a new engine family can retain, revise, or omit technologies used by its predecessor. The confirmed information at present is the new 5.7L and 6.6L displacements, their output ratings, and their planned introduction in the redesigned light-duty trucks.

Is the GMC Sierra being redesigned for 2027?

Yes. The Sierra 1500 is due to enter its next generation for 2027, alongside the Chevrolet Silverado 1500. The V8 launch is therefore part of a broader truck redesign, rather than a mid-cycle engine swap. Work Truck’s 2027 Silverado fleet guide describes a redesigned exterior and interior, additional standard safety technology, and a revised trim structure.

The new trucks are also expected to receive a GM user interface with customisable split-screen views, Apple CarPlay and Android Auto integration, mode-specific driver displays, and over-the-air update capability. Those features should not be confused with a specific current software update for an existing GMC Sierra; the available information describes the next-generation truck’s equipment and update capability, not a universal software release for older Sierra models.

What about Silverado and Sierra HD engine updates?

The confirmed 5.7L and 6.6L sixth-generation Small Block engines apply to the redesigned 1500-series pickups. Separately, reports indicate that GM is planning changes for the 2027 Silverado HD and Sierra HD powertrains, including a revised petrol 6.6-litre V8 and an updated Duramax diesel. Those heavy-duty details should be treated separately from the confirmed light-duty V8 specifications; CarBuzz’s report on the HD updates notes that some of the information stems from reported ordering-guide details and that complete specifications were not included.

What the new V8s mean for Silverado and Sierra buyers

• 2027 Silverado 1500 and Sierra 1500 buyers: expect the 5.7L and 6.6L V8s instead of the outgoing 5.3L and 6.2L options.
• Buyers wanting the highest V8 output: the 6.6L offers 481 horsepower and 501 lb-ft of torque.
• Buyers considering a base or mid-range V8: the 5.7L delivers 402 horsepower and 428 lb-ft of torque.
• Diesel and turbocharged-petrol buyers: the 3.0-litre Duramax and Enhanced TurboMax remain part of the announced four-engine line-up.
• Current Silverado and Sierra owners: the announcement does not turn the 2027 engine changes into a software update for existing trucks.

GM has confirmed the central facts behind the Silverado and Sierra V8 update, but more buying details remain to come. Until the company publishes pricing, trim availability, towing specifications, and full technical information, the clearest takeaway is that the 2027 redesign brings an all-new 5.7-litre V8 and a substantially more powerful 6.6-litre V8 to GM’s light-duty pickup range.

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