​Choosing a 2027 GMC Sierra 1500 isn't just about deciding between Elevation, AT4, Denali or another trim. One of the biggest decisions is under the hood.
The next-generation 2027 Sierra 1500 offers four engines: an enhanced TurboMax, an all-new 5.7L V8, an all-new 6.6L V8 and the 3.0L Duramax Turbo-Diesel.
And GMC made some significant changes for 2027.
The TurboMax gets more power. The previous 5.3L and 6.2L V8 choices give way to new sixth-generation 5.7L and 6.6L V8s. The Duramax remains available. And for 2027, every Sierra 1500 engine is paired with a 10-speed automatic transmission.
So which 2027 GMC Sierra engine should you choose?
Let's compare the horsepower, torque, towing capability, trim availability and the type of Sierra buyer each engine may make sense for.
2027 GMC Sierra 1500 Engine Comparison
| Engine | Horsepower | Torque | Transmission |
|---|---|---|---|
| 2.7L TurboMax | 350 hp | 455 lb-ft | 10-speed automatic |
| 5.7L V8 | 402 hp | 428 lb-ft | 10-speed automatic |
| 6.6L V8 | 481 hp | 501 lb-ft | 10-speed automatic |
| 3.0L Duramax Turbo-Diesel | 305 hp | 495 lb-ft | 10-speed automatic |
Those numbers tell an interesting story.
The 6.6L V8 produces the most horsepower and torque of the four. The Duramax makes nearly as much torque while taking a very different approach. The new 5.7L provides traditional V8 power without stepping all the way to the 6.6L. And the enhanced TurboMax produces more torque than the 5.7L V8 despite having half as many cylinders.
There isn't one engine that's automatically the right choice for every Sierra buyer.
The better question is: What do you need your truck to do?
1. Enhanced 2.7L TurboMax: 350 HP and 455 LB-FT
Don't dismiss the TurboMax simply because it's the smallest engine in the 2027 Sierra lineup.
GMC significantly upgrades it for the next-generation truck.
The 2027 TurboMax produces:
- 350 horsepower
- 455 lb-ft of torque
- 10-speed automatic transmission
Compared with the previous version, that's an increase of 40 horsepower and 25 lb-ft of torque.
GMC made several changes to get there, including a new turbocharger, upgraded fuel injection, redesigned pistons and improvements to active thermal management.
What's Interesting About the TurboMax?
Look at the torque number again.
The TurboMax produces 455 lb-ft of torque, while the new 5.7L V8 produces 428 lb-ft.
That doesn't mean the TurboMax is automatically better than the V8. Horsepower delivery, engine character, configuration, towing needs and personal preference all matter.
But it does show why the TurboMax deserves serious consideration rather than being viewed simply as the base engine.
Who Should Consider the TurboMax?
The TurboMax may be worth considering if your Sierra will primarily be used for:
- Daily driving
- Commuting
- General truck use
- Home projects
- Moderate hauling
- Buyers who don't specifically need or want a V8 or diesel
It's standard on the 2027 Sierra Pro and Elevation, making it an important engine for buyers looking at those trims.
2. New 5.7L V8: 402 HP and 428 LB-FT
The 5.7L is one of the biggest changes to the 2027 Sierra.
This new sixth-generation Small Block V8 replaces the previous 5.3L V8 as the Sierra's smaller V8 option.
It produces:
- 402 horsepower
- 428 lb-ft of torque
- 10-speed automatic transmission
- Up to 13,500 pounds of maximum available trailering when properly equipped
GMC's new V8 design incorporates higher compression, a larger throttle body, a tuned intake manifold and a dual-fuel injection system using both direct and port injection.
Why the 5.7L May Be the Sweet Spot
For a lot of Sierra shoppers, this could become the engine that sits in the middle of the lineup.
You get a naturally aspirated V8 with more than 400 horsepower without moving all the way to the 481-horsepower 6.6L.
It's also capable of the Sierra's maximum available 13,500-pound trailering rating when properly equipped.
The 5.7L is standard on two important trims: AT4 and Denali.
It's also available on Pro and Elevation.
Who Should Consider the 5.7L V8?
The 5.7L could make sense if you:
- Prefer the sound and driving characteristics of a naturally aspirated V8
- Want more than 400 horsepower
- Plan to tow regularly
- Want an AT4 or Denali
- Don't necessarily need the additional output of the 6.6L
For buyers who simply say, "I want a Sierra with a V8," this is likely to be one of the first engines they'll want to consider.
3. New 6.6L V8: 481 HP and 501 LB-FT
If your priority is gasoline V8 power, this is the engine to pay attention to.
The new sixth-generation 6.6L V8 produces:
- 481 horsepower
- 501 lb-ft of torque
- 10-speed automatic transmission
GMC describes it as its most powerful half-ton V8 ever.
For perspective, the 6.6L makes 79 more horsepower and 73 more lb-ft of torque than the new 5.7L.
It's also the only 2027 Sierra engine that breaks both the 480-horsepower and 500-lb-ft marks.
Where Can You Get the 6.6L V8?
The 6.6L is standard on Denali Ultimate.
It's also available on Denali and AT4X.
That positioning tells you something about the engine. GMC is pairing it primarily with some of the Sierra lineup's highest-end and most capable configurations.
Who Should Consider the 6.6L V8?
The 6.6L should be on your list if:
- You want maximum naturally aspirated V8 performance
- You want the most powerful Sierra 1500 gas engine
- You're considering Denali Ultimate
- You want V8 power in an AT4X
- Performance matters more to you than simply choosing the least expensive engine option
This is likely to be one of the most talked-about changes to the 2027 Sierra.
4. 3.0L Duramax Turbo-Diesel: 305 HP and 495 LB-FT
With all the attention surrounding the new V8 engines, it's easy to overlook the Duramax.
But GMC is keeping the 3.0L Duramax Turbo-Diesel in the 2027 Sierra lineup.
It produces:
- 305 horsepower
- 495 lb-ft of torque
- 10-speed automatic transmission
- Up to 12,100 pounds of maximum available trailering when properly equipped
There's another number that stands out.
When equipped with the available approximately 34-gallon fuel tank, GMC estimates the Duramax can provide more than 900 miles of highway driving range.
Official EPA fuel-economy estimates were not yet available when GMC released its initial 2027 specifications, so the final EPA numbers should be checked once they're published.
Who Should Consider the Duramax?
The Duramax may appeal to Sierra buyers who:
- Drive a lot of highway miles
- Regularly tow
- Prefer diesel torque and driving characteristics
- Want extended driving range
- Are considering AT4X
- Want an alternative to the gasoline V8 engines
The Duramax is standard on the 2027 AT4X and available on several other trims, including Pro, Elevation, AT4, Denali and Denali Ultimate.
5. 2027 Sierra 5.7L vs. 6.6L V8: What's the Difference?
This will probably be one of the most common engine comparisons for the new Sierra.
| 5.7L V8 | 6.6L V8 | |
|---|---|---|
| Horsepower | 402 hp | 481 hp |
| Torque | 428 lb-ft | 501 lb-ft |
| Transmission | 10-speed | 10-speed |
| Fuel Injection | Direct + Port | Direct + Port |
| Standard On | AT4, Denali | Denali Ultimate |
| Available On | Pro, Elevation | AT4X, Denali |
The 5.7L may be the more logical V8 for shoppers who want strong capability and traditional V8 power without moving into one of the highest-output configurations.
The 6.6L is the performance choice.
With 481 horsepower and 501 lb-ft of torque, it's aimed at someone who wants substantially more output and is already considering trims such as AT4X, Denali or Denali Ultimate.
The right choice isn't simply "bigger is better." Consider how you'll actually use the truck and which trim you want, because engine availability is closely tied to trim selection.
6. 2027 Sierra 6.6L V8 vs. 3.0L Duramax: Gas or Diesel?
This may be an even more interesting comparison.
The two engines produce surprisingly close torque numbers:
- 6.6L V8: 501 lb-ft
- 3.0L Duramax: 495 lb-ft
But horsepower is very different:
- 6.6L V8: 481 hp
- 3.0L Duramax: 305 hp
If you want the strongest acceleration and maximum gasoline V8 performance, the 6.6L is the obvious engine to examine.
If highway range, diesel characteristics and low-rpm torque are more important to you, the Duramax deserves a close look.
Your driving habits matter too.
Someone who drives relatively short distances around town may look at this decision differently from someone regularly traveling long distances or towing on the highway.
Don't choose diesel simply because you assume it's automatically the best towing engine, and don't choose the largest V8 simply because it has the biggest numbers.
Start with how you're actually going to use the truck.
7. Which 2027 GMC Sierra Engine Is Best for Towing?
If towing is your main priority, don't choose an engine based solely on torque.
The highest maximum available trailering figure GMC has announced for the 2027 Sierra 1500 is 13,500 pounds when properly equipped with the 5.7L V8.
The 3.0L Duramax offers up to 12,100 pounds of maximum available trailering when properly equipped.
But maximum trailering ratings apply only to specific configurations.
Your actual capacity depends on factors including:
- Engine
- Cab configuration
- Bed length
- 2WD or 4WD
- Trailering equipment
- Vehicle options
- Passengers
- Cargo
- Trailer tongue weight
If you already know what you'll be towing, that's actually the best place to start.
Tell us the trailer type and approximate loaded weight, and then we can work backward to the Sierra configuration that fits the job.
8. Which Engines Are Available on Each 2027 Sierra Trim?
Engine availability is closely connected to trim level.
2027 Sierra Pro
- Standard: TurboMax
- Available: 5.7L V8
- Available: 3.0L Duramax
2027 Sierra Elevation
- Standard: TurboMax
- Available: 5.7L V8
- Available: 3.0L Duramax
2027 Sierra AT4
- Standard: 5.7L V8
- Available: 3.0L Duramax
2027 Sierra AT4X
- Standard: 3.0L Duramax
- Available: 6.6L V8
2027 Sierra Denali
- Standard: 5.7L V8
- Available: 6.6L V8
- Available: 3.0L Duramax
2027 Sierra Denali Ultimate
- Standard: 6.6L V8
- Available: 3.0L Duramax
Availability may also depend on cab, bed, drivetrain and production configuration, particularly as the next-generation Sierra begins arriving at dealerships.
9. Which 2027 GMC Sierra 1500 Engine Should You Choose?
Here's a simple way to start narrowing it down.
Consider the TurboMax if...
You want strong torque and everyday truck capability without specifically needing a V8 or diesel. It's particularly relevant if you're shopping Pro or Elevation.
Consider the 5.7L V8 if...
You want traditional naturally aspirated V8 power, more than 400 horsepower and strong towing capability without stepping all the way to the 6.6L. It's also the standard engine for AT4 and Denali.
Consider the 6.6L V8 if...
You want maximum gasoline performance. At 481 horsepower and 501 lb-ft of torque, it's the most powerful engine in the 2027 Sierra 1500 lineup.
Consider the 3.0L Duramax if...
You value diesel torque, highway range and towing capability, particularly if you spend a lot of time on the road. It's also the standard engine in AT4X.
Ultimately, we wouldn't choose an engine based on one specification.
Choose your engine based on what you tow, how much you drive, where you drive and which Sierra trim you actually want.
2027 GMC Sierra 1500 Engine FAQs
What engines are available in the 2027 GMC Sierra 1500?
The 2027 Sierra 1500 offers four engines: a 2.7L TurboMax, new 5.7L V8, new 6.6L V8 and 3.0L Duramax Turbo-Diesel. All four are paired with a 10-speed automatic transmission.
How much horsepower does the 2027 Sierra 5.7L V8 have?
The new 5.7L V8 produces 402 horsepower and 428 lb-ft of torque.
How much horsepower does the 2027 Sierra 6.6L V8 have?
The new 6.6L V8 produces 481 horsepower and 501 lb-ft of torque.
Is the 2027 Sierra 6.6L V8 the same engine as the Sierra HD 6.6L gas engine?
The 2027 Sierra 1500 uses a new sixth-generation 6.6L Small Block V8 developed for the next-generation light-duty Sierra. Shoppers should not assume specifications or applications are interchangeable with Sierra Heavy Duty powertrains.
Does the 2027 GMC Sierra still offer a Duramax diesel?
Yes. The 3.0L Duramax Turbo-Diesel continues for 2027 with 305 horsepower and 495 lb-ft of torque.
Which 2027 Sierra engine has the most horsepower?
The 6.6L V8 has the most horsepower at 481 hp.
Which 2027 Sierra engine has the most torque?
The 6.6L V8 produces the most torque at 501 lb-ft, followed closely by the 3.0L Duramax at 495 lb-ft.
Which 2027 Sierra engine can tow the most?
GMC lists up to 13,500 pounds of maximum available trailering for the 5.7L V8 when properly equipped. Actual towing capacity varies considerably by vehicle configuration and equipment.
What engine comes in the 2027 Sierra AT4?
The new 5.7L V8 is standard in the 2027 Sierra AT4, while the 3.0L Duramax Turbo-Diesel is available.
What engine comes in the 2027 Sierra AT4X?
The 3.0L Duramax Turbo-Diesel is standard in the 2027 AT4X. The new 6.6L V8 is available.
What engine comes in the 2027 Sierra Denali?
The 5.7L V8 is standard in Denali. The 6.6L V8 and 3.0L Duramax are available.
What engine comes in the 2027 Sierra Denali Ultimate?
The 6.6L V8 is standard in Denali Ultimate, while the 3.0L Duramax is available.
Find the Right GMC Sierra 1500 Engine at Elizabeth City GMC
The expanded 2027 Sierra engine lineup gives buyers more choices, but it also makes choosing the right configuration more important.
A daily-driven Elevation with TurboMax serves a very different purpose from a Duramax AT4X or a 6.6L V8 Denali Ultimate.
At Elizabeth City GMC, we can help you compare the engine, trim and equipment combinations based on how you actually plan to use your truck.
We serve Sierra shoppers throughout Elizabeth City, Hertford, Edenton, Camden, Currituck, Moyock and the Outer Banks, along with customers traveling from Chesapeake, Suffolk, Virginia Beach and other parts of southeastern Virginia.
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Elizabeth City GMC
1197 Highway 17 South
Elizabeth City, NC 27909
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