The humble diesel engine has not had an easy time in recent history. The Dieselgate scandal cratered diesel’s popularity, and today’s record-high diesel prices might have some buyers rethinking buying a diesel for their next vehicle. But none of that has deterred General Motors. Even as its competition runs to electrification and smaller engines, General Motors thinks the future of the pickup trucks is not exactly a hybrid, but burly diesels and hugely powerful V8s.
General Motors is gearing up to launch its next-generation pickup trucks, the 2027 Chevrolet Silverado and the 2027 GMC Sierra. There has been a drip-feed of information regarding the new trucks. Recently, we learned that the truck will get two new V8s, but they won’t have oil dipsticks. We also know that the new trucks will be filled to the brim with technology, including three dashboard screens.
Both of those are surprising on their own, but then there’s what Automotive News pointed out today. While Ford and Toyota have hybrid pickup trucks on the market and Ram is actively developing one, General Motors is going in an entirely different direction. General Motors has decided to double down on diesel, serving a niche of buyers that its competitors have abandoned. Yet, amazingly, this plan isn’t anything new for the General.
We Finally Know More About GM’s New V8s
Today, General Motors has finally revealed the specs of the powerplants that will propel its new generation of half-ton trucks. As I reported yesterday, buyers of the 2027 Chevrolet Silverado and the 2027 GMC Sierra will have the option of four diverse engine choices.
Starting from the base engine, the 2.7-liter TurboMax inline-four will be making a return for the 2027 model year. The TurboMax will now output 350 horsepower and 455 pound-feet of torque, which is a 40-horse upgrade over the 2026 model. As Automotive News writes, this engine is being pitched as the affordable option for folks who might not need the hauling prowess of either V8 or the incredible range of the diesel.
As I mentioned yesterday, the engines that won’t be returning for 2027 are the 5.3-liter L84 V8 and the infamous 6.2-liter L87 V8. GM is replacing them with 5.7-liter L76 V8 and 6.6-liter L78 V8 powerplants designed around GM’s new Gen-Six small-block V8 architecture. Here’s what GM said it did to create these new engines:
To generate more horsepower and torque from the new light-duty truck V8s, GM engineers applied several key enablers:
– Increased displacement from 5.3L and 6.2L to 5.7L (350 cubic inches) and 6.6L (400 cubic inches), respectively, by increasing piston stroke 6 mm.
– Higher compression ratio for more efficient combustion.
– More airflow via larger throttle diameters.
– New intake manifolds with tuned runners to manage the additional airflow.
The new engines feature 4.4-inch bore spacing, a cam-in-block design, two valves per cylinder, and rocker arms. The 5.7-liter L76 sounds like a screamer with 402 horsepower and 428 pound-feet of torque on deck, a considerable upgrade over the 355 horsepower and 383 pound-feet of twist from the outgoing 5.3 L84 V8.
Then there’s the 6.6-liter L78, which fires out an impressive 481 horsepower and 501 pound-feet of torque, making it the hottest naturally aspirated V7 in the light-duty class. It’s a decent bit healthier than the 420 horsepower and 460 pound-feet of torque in the outgoing 6.2-liter L87 V8, and will hopefully not be as controversial.
America’s Only Purveyor Of Half-Ton Diesels Doubles Down
The real twist is GM’s continued adoration of diesel power. The LZ0 3.0-liter Duramax straight-six diesel that allows GM’s twins to be the only half-ton diesels in America is back for an encore. Output in the 2027 version is unchanged at 305 horsepower and 495 pound-feet of torque. The other good news is that the 2027 Silverado’s tow rating is up to 13,700 pounds, an upgrade of 400 pounds compared to the outgoing model. The 2027 Sierra also gets a 400-pound tow capacity upgrade to 13,500 pounds.
Curiously, the 13,700-pound capacity is achieved with the 5.7-liter V8. The Duramax, at least at launch, will be rated for up to 12,100 pounds of towing. This is the inverse of how the current Silverado and Sierra work, where the maximum tow rating is achieved through the diesel or the 6.2-liter V8. To be fair to the diesel, this is exactly what happened early on in the 3.0-liter Duramax’s run, when towing was limited to 9,300 pounds. So, GM could always make changes to pump up the diesel’s numbers later.
The more surprising thing is that GM is even bothering with a diesel half-ton at all. Ford, Ram, and Jeep abandoned their diesel half-tons a long time ago. Likewise, we now live in a world where the national average price of diesel is $6.39 per gallon. Unless you’re a total diesel nut as I am, I wouldn’t blame you for not seeing the point in getting a diesel. Add in the emissions equipment that’s costly to repair outside of warranty, and it makes you wonder why GM is continuing to bother with the idea.
However, as I’ve explained in the past, General Motors got back into the diesel passenger car market in 2014 to battle Volkswagen’s TDIs. It was a momentous occasion, considering that it had been nearly three decades since GM last sold a diesel car in America.
Then GM used the Dieselgate scandal as an opportunity. Volkswagen might have eroded the public’s trust in passenger car diesels, but to General Motors, the cheating was the problem, not the diesel engine. With Volkswagen making a hard pivot to electric vehicles, General Motors identified a void in the market for light-duty diesel vehicles. General Motors would churn out diesels in the Chevrolet Equinox, GMC Terrain, Chevrolet Cruze, Chevrolet Colorado, GMC Canyon, Chevrolet Tahoe/Suburban, GMC Yukon/Yukon XL, Cadillac Escalade, and yep, the Chevrolet Silverado 1500 and GMC Sierra 1500.
Today, GM’s list of light-duty diesels has been reduced to the Tahoe and Suburban, the Yukon, the Silverado, and the Sierra. But even that is just staggering. Ford isn’t going to sell you an Expedition with a Power Stroke, and Dodge apparently doesn’t have the bravery to put a Cummins in the Durango. What gives? Automotive News gives some insight into what GM is thinking:
“It’s not one engine for everybody,” GM President Mark Reuss said during a media event at the company’s engine plant here. “It’s the freedom to choose the engine that fits your work, lifestyle and priorities.”
For Silverado and Sierra buyers, GM sees its diesel powertrain as having some advantages over a hybrid option, including driving range. The redesigned pickups’ Duramax engine allows more than 900 miles of highway driving on a 34-gallon tank. “If you look at the performance and efficiency but also raw performance and range, hybrids really don’t do it,” Reuss said. “It’s a bit different adding a hybrid system to an existing powertrain and trying to get the efficiency out of it like that.”
“Different customers need different combinations of capability, range, affordability, towing confidence and convenience,” Reuss said. “Our aim is to meet them where they are.”
At first, I was taken aback by what Reuss said, but I thought about it for a minute. I get it. I tested the Toyota Tundra TRD Pro in 2023 and came out thoroughly unimpressed with its hybrid twin-turbo V6’s efficiency. When towing, the TRD Pro returned worse fuel economy than I got pulling the same trailer with a regular naturally aspirated V8 gasoline engine. The 2026 Chevrolet Silverado 1500 diesel I tested earlier this year bested the TRD Pro’s towing fuel economy by a whopping 42 percent. Even when driving around empty, the Tundra couldn’t beat the diesel.
To be fair to the Tundra, Toyota did say it didn’t make a hybrid half-ton for efficiency, but to prove that hybrids could do real truck stuff. It’s also not just the Tundra. Some Ford F-150 PowerBoost owners claim that going hybrid doesn’t help their towing fuel economy, either. That’s not to say that hybrids are bad. I adored the Tundra for its instant power and towing prowess. But it also makes me understand why GM is doubling down on diesel. Likewise, GM also gets to claim that it’s the only manufacturer with a half-ton lineup featuring a four, two V8s, and a diesel!
GM’s commitment to diesel goes beyond the call of light-duty. The automaker’s heavy-duty Silverado and Sierra trucks are also reportedly getting updated diesel power. According to GM Authority, succeeding the 6.6-liter L5P Duramax V8 diesel will be the L6P. As of publication, General Motors is still quiet about the spec sheet of that one. It will reportedly be joined by the 6.6-liter L8S gasoline V8, which is expected to be an updated version of the current 6.6-liter L8T V8. Exact numbers have not yet been confirmed for this engine.
Then there’s potentially one more engine out there. For the past couple of years, GM-focused publications and enthusiasts have been talking about a rumored 8.3-liter Duramax diesel, which would be a sort of pickup truck diesel to rule them all. GM hasn’t said anything about this engine, so it may not even exist. But the idea of it is fun to think about. Currently, Ford’s 6.7-liter Power Stroke V8 is the most powerful pickup diesel on the market. Could a big lump of General Motors muscle surpass the Power Stroke’s 1,200 pound-feet of torque? I don’t know why, but I’m getting excited just thinking about it.
GM’s Been Working On These Engines For Years
Anyway, back to the engines we do know about. According to Automotive News, GM’s investment in V8s is not a reaction to the changing political climate. From Automotive News:
The new engines and pickup redesigns come at a critical moment for GM. It needs the profits from its high-margin pickups to compensate for the import tariffs it’s paying and the $11 billion in write-downs it took over the past year on investments in electric vehicle manufacturing. While CEO Mary Barra says EVs remain the company’s “North Star,” the new V-8s and GM’s high hopes for its gasoline-powered pickups suggest that an all-electric future remains distant.
“We spent effort and time on EVs, and we will continue to do that. But we never let our foot up off the throttle on our naturally aspirated V-8s or any of our powertrain lineups,” said Mark Dickens, GM’s executive chief engineer for full-size trucks and SUVs. “Fundamentally, these engines didn’t happen overnight. This is years of development that’s gone into these engines.”
The engines were in development before the Trump administration moved to slash fuel economy standards, GM executives said.
The big question is, will focusing on V8s and diesels pay off in the end? My crystal ball is currently showing me a blue screen, so I’m unable to tell you.
What I can say is that GM’s trucks are seemingly getting even more exciting than they already are. Just the fact that the lowest engine in the lineup still makes 350 horsepower is awesome. I also stand by what I said earlier this year when I said that the Silverado 1500 diesel is one of my all-time favorite pickup trucks. Maybe it’s just me, but it’s so cool that GM isn’t just keeping diesel around, but is actively rooting for it. Me too, GM, me too.
Top graphic images: GM
