The 5.5-liter V8 doesn't share a single component with GM's other small-block V8s.
The 5.5-liter LT6 engine found in the upcoming Chevrolet Corvette Z06 is a truly special powerplant. GM's engineers knew the upcoming Porsche fighter had to have a brilliant power source and, to that end, purchased a Ferrari 458's engine to benchmark against. Chevy's hard work has paid off, as the naturally aspirated motor develops an almighty 670 horsepower and 460 lb-ft of torque. What's more, it can rev up to 8,600 rpm.
The Bowtie brand also revealed that the LT6 has several astronaut-inspired easter eggs, with some even serving a functional purpose. All of this is very nice, but because GM has so many V8s under its umbrella, surely the LT6 is a parts bin special? Well no, actually - far from it.
Speaking with SAE International, chief engineer Jordan Lee noted the LT6 shares nothing with any of Chevy's "small-block" V8s, so don't call it one. The LT6 has virtually no connection to the engine type in general, never mind any specific Chevy motor. The only common trait is the 4.4-inch bore-center spacing, which would be an unfair standalone measurement to which to compare other engines. As Lee says, "This is a unique engine on its own."
With Chevrolet's goal of making the Z06 a true world-beater, engineers approached the design of the new engine with a fresh outlook. First and foremost was weight reduction. The LT6's forged titanium connecting rods are 21% lighter than the items found in the 7.0-liter LS7 V8 from the C6 Z06, for example. What's more, the forged aluminum pistons are a notable 8% lighter than the LS7's, too. This makes it incredibly light - despite the 175-hp advantage over the Stingray's LT2 V8, it weighs just 2.2 pounds more.
While the development team had an initial goal of 650 hp, they soon saw the LT6 was capable of even more power.
Assistant chief engineer, Dustin Gardner, said, "We quickly realized we had 650 in the bag [...] I think it's going to stand the test of time of being one of the true icons." Interestingly, design system engineer Yoon Lee says that the production engine makes more power than the racing version (due to endurance racing regulations). With GM spearheading myriad EV projects, this may be the last engine of its kind that we see from the carmaker, but if so, it's a brilliant way to go out.