Rivard Buick GMC · Tampa, FL
2027 GMC Sierra 1500 Engines
The 2027 Sierra 1500 launches with four confirmed engines, headlined by two all-new sixth-generation Small Block V8s: a 5.7L and a 6.6L, the most powerful naturally aspirated V8 in its class. The enhanced TurboMax 2.7L and the class-exclusive Duramax 3.0L Turbo-Diesel round out the lineup, and every engine pairs with a 10-speed automatic. Here is everything GMC has confirmed, what remains unannounced, and how the new lineup compares with the engines it replaces.
The Lineup
What Engines Will the 2027 GMC Sierra 1500 Offer?
Last updated July 14, 2026 by Rivard Buick GMC
GMC confirmed four engines for the 2027 Sierra 1500 at the June 25, 2026 reveal: an all-new sixth-generation 6.6L V8 (standard on Denali Ultimate and the most powerful naturally aspirated V8 in its class), an all-new sixth-generation 5.7L V8, the class-exclusive Duramax 3.0L Turbo-Diesel inline-six, and an enhanced TurboMax 2.7L turbocharged four-cylinder with best-in-class standard torque. Every engine is paired with a 10-speed automatic transmission.
What GMC has not released: horsepower and torque figures, towing and payload ratings, fuel economy, and which engines are available on which trims beyond the Denali Ultimate's standard 6.6L. GM has said detailed specifications will be announced closer to launch. This page separates what is confirmed from what press coverage estimates, and we update it as GM releases official numbers.
The Headliner
The All-New 6.6L V8: Most Powerful Naturally Aspirated V8 in Its Class
The sixth-generation 6.6L V8 is the flagship engine of the 2027 Sierra 1500 and comes standard on the Denali Ultimate. GMC's class claim sets a clear performance floor: to be the most powerful naturally aspirated V8 in the full-size light-duty class, it has to outmuscle every competitor's NA V8 and GM's own outgoing 420-horsepower 6.2L. Independent coverage from GM Authority estimates output around 475 horsepower, though GM has not published official figures.
All-New · Gas V8
6.6L V8
Sixth-generation Small Block architecture with advances in combustion, cooling, and control systems, plus a new fuel injection system.
- GenerationAll-new sixth-generation Small Block V8
- Class PositionMost powerful naturally aspirated V8 in its class (confirmed by GMC)
- OutputNot announced. Press estimates: approximately 475 hp (GM Authority)
- Transmission10-speed automatic
- AvailabilityStandard on Denali Ultimate; availability on other trims not announced
- EngineeringNew fuel injection system tuned across daily driving, towing, and off-road use
The Volume V8
The All-New 5.7L V8
The second new engine is a 5.7L sixth-generation Small Block V8, positioned as the strong, capable mainstream V8 of the lineup, the successor role held by the 5.3L in the outgoing generation. It shares the sixth-generation architecture and new fuel injection system with the 6.6L. GM Authority estimates output in the neighborhood of 400 horsepower, which would put it well above the outgoing 5.3L's 355 horsepower, but GM has not confirmed a number.
All-New · Gas V8
5.7L V8
The mainstream V8 of the fifth-generation Sierra, built on the same all-new architecture as the 6.6L.
- GenerationAll-new sixth-generation Small Block V8
- RoleSuccessor to the volume V8 position held by the outgoing 5.3L
- OutputNot announced. Press estimates: approximately 400 hp (GM Authority)
- Transmission10-speed automatic
- AvailabilityTrim availability not announced
- EngineeringShared combustion, cooling, and control advances with the 6.6L
Class Exclusive
Duramax 3.0L Turbo-Diesel: Still the Only Diesel in the Class
The Duramax 3.0L Turbo-Diesel inline-six continues into the 2027 Sierra 1500, and GMC's claim holds for the new generation: no other competitor in the class offers an available diesel. In the outgoing truck the Duramax produced 305 horsepower and 495 lb-ft of torque and delivered the strongest highway fuel economy in the lineup, which is why it built a loyal following with owners who tow. Updated 2027 output and towing figures have not been announced.
Class-Exclusive Diesel
Duramax 3.0L Turbo-Diesel
The torque-rich, efficiency-focused choice, and the only diesel offered by any truck in this class.
- ConfigurationTurbocharged 3.0L inline-six diesel
- Class PositionClass-exclusive: no competitor offers an available diesel (confirmed by GMC)
- 2027 OutputNot announced. Outgoing generation reference: 305 hp / 495 lb-ft
- Transmission10-speed automatic
- Best ForTowing range and highway efficiency
- AvailabilityTrim availability not announced
The Standard Bearer
Enhanced TurboMax 2.7L: Best-in-Class Standard Torque
The TurboMax 2.7L turbocharged four-cylinder returns in enhanced form and carries a confirmed GMC claim: best-in-class standard torque. In the outgoing generation the TurboMax made 310 horsepower and 430 lb-ft, more torque than some competitors' V8s, and served as the standard engine on volume trims. GMC has not detailed what the 2027 enhancements change or published updated figures.
Enhanced Turbo Four
TurboMax 2.7L
The proven turbocharged four-cylinder, enhanced for 2027 with best-in-class standard torque.
- ConfigurationTurbocharged 2.7L inline four-cylinder
- Class PositionBest-in-class standard torque (confirmed by GMC)
- 2027 OutputNot announced. Outgoing generation reference: 310 hp / 430 lb-ft
- Transmission10-speed automatic (up from 8-speed in the outgoing truck)
- RoleExpected standard engine on volume trims; official trim mapping not announced
- Best ForDaily driving with serious torque and lower cost of entry
Signal vs. Noise
2027 Sierra 1500 Engine Specs: Confirmed, Estimated, Not Announced
The table below separates GMC's official statements from independent press estimates and open questions. Anything marked Estimate comes from automotive press analysis, not from GM, and can change when official figures drop.
| Topic | Status | Details |
|---|---|---|
| Engine Lineup | Confirmed | Four engines: all-new 6.6L V8, all-new 5.7L V8, Duramax 3.0L Turbo-Diesel, enhanced TurboMax 2.7L. |
| Transmission | Confirmed | 10-speed automatic paired with every available engine. |
| 6.6L Class Claim | Confirmed | Most powerful naturally aspirated V8 in its class, per GMC. Standard on Denali Ultimate. |
| 6.6L Output | Estimate | Approximately 475 hp per GM Authority analysis. The class claim requires beating GM's own outgoing 420 hp 6.2L and every competitor NA V8. Official figure not released. |
| 5.7L Output | Estimate | Approximately 400 hp per GM Authority analysis. Official figure not released. |
| TurboMax Claim | Confirmed | Best-in-class standard torque, per GMC. Updated output figures not released. Outgoing reference: 310 hp / 430 lb-ft. |
| Duramax Diesel | Confirmed | Class-exclusive 3.0L Turbo-Diesel continues. Updated output not released. Outgoing reference: 305 hp / 495 lb-ft. |
| V8 Engineering | Confirmed | Sixth-generation Small Block architecture with advances in combustion, cooling, and control systems, and a new fuel injection system tuned for daily driving through towing and off-road use. |
| Towing & Payload | Not Announced | Maximum towing and payload ratings have not been published. Available Super Cruise with trailering is confirmed across more of the lineup than any previous Sierra. |
| Fuel Economy | Not Announced | EPA figures will be published closer to launch. |
| Engine-by-Trim Availability | Not Announced | Only confirmed pairing: 6.6L V8 standard on Denali Ultimate. Full trim-by-engine mapping arrives with the order guide. |
| Hybrid or PHEV | Not Announced | GMC has not announced any hybrid powertrain for the 2027 Sierra 1500. Electric truck buyers are served by the separate Sierra EV. |
Sources include the official GMC press release on the 2027 Sierra 1500 and analysis from GM Authority, Car and Driver, and MotorTrend. Rivard Buick GMC updates this page as official specifications are released.
Generation Change
What Happened to the 5.3L and 6.2L V8s?
The familiar 5.3L and 6.2L V8s do not carry into the fifth-generation Sierra. Both are replaced by the new sixth-generation Small Block family: the 5.7L steps into the volume V8 role, and the 6.6L takes over the top spot from the 6.2L. If you specifically want a 5.3L or 6.2L Sierra, the 2026 model year is the last chance to buy one new, and we have them in stock in Tampa today.
2026 Sierra Engines
Final Year, In Stock- 2.7L TurboMax I-4310 hp / 430 lb-ft, 8-speed automatic
- 5.3L EcoTec3 V8355 hp / 383 lb-ft, the long-running volume V8
- 6.2L EcoTec3 V8420 hp / 460 lb-ft, the outgoing performance flagship
- 3.0L Duramax Diesel305 hp / 495 lb-ft, efficiency and towing champion
- StatusPublished specs, published pricing, available now at Rivard Buick GMC Tampa
2027 Sierra Engines
Late 2026- Enhanced 2.7L TurboMax I-4Best-in-class standard torque, now with a 10-speed automatic
- All-New 5.7L V8Sixth-generation Small Block, replaces the 5.3L role. Est. ~400 hp
- All-New 6.6L V8Most powerful NA V8 in class, replaces the 6.2L role. Est. ~475 hp
- 3.0L Duramax DieselContinues as the only diesel in the class
- StatusOutput figures, towing, and pricing to be announced before launch
What Is the Sixth-Generation Small Block?
The Small Block is GM's V8 family dating back to 1955, and the engines in today's trucks are fifth-generation designs introduced in 2014. The 2027 Sierra debuts the sixth generation: new displacements (5.7L and 6.6L), a new fuel injection system, and updated combustion, cooling, and control systems engineered for refinement and durability across daily driving, towing, and off-road use. It is the first new Small Block generation in over a decade, which is a large part of why this redesign matters.
Capability
Built to Tow, With Super Cruise That Tows With You
Official towing and payload ratings for the 2027 Sierra 1500 have not been released. What is confirmed: available Super Cruise with trailering expands across more of the lineup than any previous Sierra, supporting hands-free driving on more than 600,000 miles of compatible roads, and the Denali Ultimate includes a standard three-year subscription. For Tampa Bay owners pulling boats to the ramp or equipment across Hillsborough County, the pairing of new V8 power and hands-free trailering is the headline capability story of this generation. Read more about how it works on our Super Cruise page.
Get in Line First
Reserve Your Spot for the 2027 Sierra 1500
GM has not opened the retail order bank for the 2027 Sierra 1500, and engine output figures land before launch. Join the Rivard Buick GMC reservation list and you will hear from us the day ordering opens, with first access to allocation at Tampa Bay's highest-volume GMC dealer. Tell us in the comments which engine and trim you are targeting and we will match you to it when the order guide drops.
Want a V8 truck now? The 2026 Sierra 1500 with the proven 5.3L, 6.2L, TurboMax, and Duramax engines is on the ground today with published pricing.
2027 Sierra Reservation
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FAQ
2027 Sierra 1500 Engines: Frequently Asked Questions
What engines will the 2027 GMC Sierra 1500 have?
Four confirmed engines: an all-new sixth-generation 6.6L V8 (standard on Denali Ultimate), an all-new sixth-generation 5.7L V8, the class-exclusive Duramax 3.0L Turbo-Diesel inline-six, and an enhanced TurboMax 2.7L turbocharged four-cylinder with best-in-class standard torque. All four pair with a 10-speed automatic transmission.
How much horsepower will the 2027 Sierra 1500 have?
GM has not released official output figures. GMC has confirmed the 6.6L V8 is the most powerful naturally aspirated V8 in its class, which means it must exceed GM's own outgoing 420-horsepower 6.2L and every competitor's naturally aspirated V8. Automotive press analysis estimates roughly 475 horsepower for the 6.6L and roughly 400 horsepower for the 5.7L. Official numbers will be announced closer to launch, and we will update this page when they are.
Is the 2027 Sierra 1500 replacing the 5.3L and 6.2L V8s?
Yes. The fifth-generation 5.3L and 6.2L EcoTec3 V8s do not continue into the 2027 Sierra 1500. They are replaced by the all-new sixth-generation 5.7L and 6.6L Small Block V8s. The 2026 Sierra 1500 is the final model year for the 5.3L and 6.2L.
Does the 2027 Sierra 1500 still offer a diesel engine?
Yes. The Duramax 3.0L Turbo-Diesel inline-six continues in the 2027 Sierra 1500, and it remains class-exclusive: no other truck in the class offers an available diesel. Updated output figures have not been announced. In the outgoing generation it produced 305 horsepower and 495 lb-ft of torque.
What transmission does the 2027 Sierra 1500 use?
A 10-speed automatic is paired with every available engine, including the TurboMax 2.7L, which used an 8-speed in the outgoing generation.
Will there be a hybrid 2027 GMC Sierra?
GMC has not announced a hybrid or plug-in hybrid powertrain for the 2027 Sierra 1500. The confirmed lineup is two gas V8s, the TurboMax turbo four, and the Duramax diesel. Buyers who want an electric GMC truck are served by the separate Sierra EV.
Which engine comes standard on the Denali Ultimate?
The all-new 6.6L V8 is standard on the 2027 Sierra 1500 Denali Ultimate. It is the only confirmed engine-to-trim pairing so far; the full engine availability map for Pro, Elevation, AT4, Denali, and AT4X arrives with the official order guide.
When can I order a 2027 Sierra 1500?
GM has not opened the retail order bank or published an order guide. First trucks are expected at dealerships before the end of the 2026 calendar year. Rivard Buick GMC Tampa is maintaining a reservation list, and everyone on it hears from us the day ordering opens. Reserve your spot here.
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