3 Of The Most Powerful GMC V6 Engines Ever Made

General Motors, the owner of GMC, has made all sorts of impressive powertrains over the years. Muscle cars with V8s are sprinkled all throughout its history, as are powerful pickup trucks, sporty sedans, and supercar competitors. The newest Corvette ZR1, for example, offers a vision into what GM can do when they decide to add a bit of forced induction to their top-performing sports car — breaking into the four-digit horsepower territory is no small task.

Searching through the history of the iconic American brand, however, it's hard to find many iconic V6 models. Sure, there's the Grand National from Buick (another GM-owned company) but what about GMC V6s? Why don't they get any love? Certainly, there must be some big, powerful V6s hidden in the history of General Motors. And why not amongst its truck brand, GMC? Well, it turns out that while they aren't as abundant in GMC's lineup throughout the years as you might hope for, there are a few pretty powerful V6 engines worth focusing on.

The 4.3-liter V6 under the hood of GMC's Typhoon and Syclone is considered one of the greatest American V6s ever made. The Typhoon and Syclone were small-SUV and small-pickup siblings made by GMC in the 1990s, both of which came with an epic motor: the turbocharged V6, which put out 280 horsepower and 350 lb-ft of torque. That barely beats out something like the current naturally aspirated V6 under the hood of GMC's Savana Van today (it has 276 horsepower and 298 lb-ft of torque) but they were big numbers for the day.

Back in 1991, Car and Driver put the Syclone up against a Ferrari 348ts and the plucky little GMC came out on top. It went from 0-60 mph in 5.3 seconds, and it passed the quarter mile in 14.1 seconds at 93 miles per hour. By comparison, the Ferrari took 6.0 seconds to reach 60 mph and 14.5 seconds to reach the quarter mile. Anytime something with a boxy shape and near-square headlights can outpace an Italian sports car from the same era, heads turn. 

If you're interested in engines, especially big-power American engines, you likely know the term "big block" as it relates to muscle cars and especially V8 engines. But GMC made a big-block V6 that certainly earned the large-and-in-charge designation without needing eight cylinders. The 478 name refers to the engine's cubic inches — 478 of em'. That's 7.8-liters of displacement from an engine with just six cylinders. To put that into context, five of General Motors 10 biggest V8 engines offer less displacement.

The big-block V6 was made from 1960 to 1974 for GMC's 6500-series commercial pickup trucks, and it is still one of the biggest V6 engines ever produced. The big block wasn't a tower of power, but it did have massive torque. It produced 254 horsepower – modest by today's standards — and 442 lb-ft of torque. Several GMC models have more horsepower, but you'll have a hard time finding a GMC with a V6 and more torque. It's also unlikely that you'll see a 478 at any classic car shows, since it was mostly used in vehicles like dump trucks and school buses. Even if its elusive, it's still a very unique engine. 

While vehicles like the current GMC Canyon and GMC Acadia are powered exclusively by four-cylinder engines, models from just a few years back got a 3.6-liter V6 under the hood that put out a respectable amount of power. In 2023, GMC redesigned the Canyon (and in 2024 the Acadia followed suit) and took out the 3.6-liter V6 entirely, replacing it with a turbocharged 2.7-liter four-cylinder engine.

While not as iconic as the big-block V6 or the Syclone's turbocharged V6, the 3.6-liter engine still offered 308 horsepower in the Canyon. In GMC's Acadia SUV, the 3.6-liter V6 made even more power — a total of 310 horses.

To help put the Syclone's straight-line speed into perspective, look no further than these modern V6-powered GMC's. When Car and Driver tested one back in 2022, the Canyon went from 0-60 mph in 6.7 seconds and crossed the quarter-mile mark in 15.2 seconds. The Acadia took 6.1 seconds to reach 60 mph.