The V8 Is So Back: GM's New Truck Motors Make Up to 481 Horsepower, Have Upgraded Internals

• What's new: GM is launching its sixth generation of small block V8s, which make up to 481 hp.
• Why it matters: These advanced engines promise more power and efficiency and replace its recall-plagued outgoing models.
• Edmunds says: In GM's truck world, it's a V8 party, until someone says otherwise. 

The 6.6-liter is the most powerful naturally aspirated V8 in the segment, outgunning the Ram's 5.7-liter Hemi V8 (395 hp, 410 lb-ft) and Ford's 5.0-liter Coyote V8 (400 hp, 410 lb-ft). The Toyota Tundra does not currently offer a V8 engine.

The sixth generation of small block V8 engines will power the Chevrolet Silverado and GMC Sierra full-size trucks, which are expected to arrive late this year, and will roll out to other GM models starting next year. The new small block V8 family launched earlier this year in the Chevy Corvette, which runs a 6.7-liter V8.

GM is investing in V8s after more than a year of issues and recalls plaguing its outgoing V8-powered models. The automaker was forced to recall hundreds of thousands of 6.2-liter V8s for connecting rod and crankshaft issues that could lead to engine failures.

Still, GM is trying to make a fresh start with these new V8s. It noted the new engines have logged more than 1.5 million miles of testing and validation and are significantly upgraded over their predecessors.

New V8s, familiar numbers

There's an old saying that there's no replacement for displacement, and GM's new V8s are dusting off some magical numbers. The 5.7-liter measures 350 cubic inches, the 6.6 is 400 cubic inches, and the Corvette's motor stretches out to the classic 409 displacement.

"That's heritage," said Norman Peralta, executive chief engineer for engines and batteries.

In addition to the larger displacements, GM upgraded the V8 engines with higher compression ratios, created more air flow with larger throttle diameters, and added a new lubrication system and new intake manifolds. The engines also get a new fuel system that uses direct and port injection.

Don't sleep on the diesel or turbo four-cylinder

The trucks will continue to offer an upgraded four-cylinder TurboMax engine rated at 350 hp and 455 lb-ft of torque (up 40 hp and 25 lb-ft) that can tow up to 9,400 pounds. It gets a new turbocharger, an upgraded fuel injection system, enhanced active thermal management and new pistons. 

The 3.0-liter Duramax turbodiesel rated at 305 hp and 495 lb-ft and with maximum towing of 12,100 pounds is also offered. All of the engines are teamed with a 10-speed automatic transmission.

"There's no single Silverado or Sierra customer," GM's president, Mark Reuss, said. "It's not one engine for everybody. It's the freedom to choose."

With the Trump administration's planned rollback of fuel economy standards this year and the ending of the federal tax credit for electric vehicles last fall, Detroit's truck makers have retrenched, staking their futures again on V8 models. Ram and Ford have also cast aside their electric full-size trucks (for now, a smaller Ford EV pickup called Fathom is set to make its debut next year), though Chevy and GMC still have the Silverado and Sierra EVs.

With V8s, the past is never dead

GM, however, argues its new V8s are forward-facing and can be adjusted should federal emissions and fuel economy standards grow stricter, and pointed out the new small block family has been in development for several years.

"We feel really confident in these to go far into the '30s," Peralta said.

Still, the history ran deep during GM's preview event for the V8s, held in its ancestral home of Flint, 118 years to the day the company was founded. GM has made small block V8s in Flint since 1955, and it recently spent $918 million to support building its new family of engines. The automaker will also build the V8s at its factories in Buffalo, N.Y., and St. Catharines in Ontario, Canada.

GM executives didn't comment on its plans for a potential hybrid model, though Ford sells its 3.5-liter hybrid model in high volume. Currently, GM is positioning the diesel, which offers up to 900 miles of range, as its efficiency solution. That said, ultimately, the company says electrics will be its future.

"We know EVs are the endgame for our industry and we're not walking away from it," Reuss said.

Until then, the era of V8s continues.