Every generation of the Chevrolet Corvette Z06 has raised the bar with a record-setting engine. The first Z06 featured the highest horsepower small-block in history. The legendary 327 cubic-inch V8 held this record for nearly forty years. Now, Chevrolet is building the 2023 Corvette Z06 around an unusual new small-block. This engine, the LT6, leverages exotic car technology to make 670 horsepower–without a turbo or supercharger. As a result, it is the most powerful naturally-aspirated V8 ever installed in a production car. Here’s how Chevrolet outdid itself yet again.

The 1963 Chevrolet Corvette Z06 came with a 375 horsepower, 327 cubic-inch V8

When Chevrolet first introduced the Z06 package, it was a suspension and brake option on the top-trim 1963 Corvette. Customers had to first order the Corvette Stingray with the “fuelie” or fuel-injected V8. 

By 1964, this 327 cubic-inch V8 made 375 horsepower. It was the highest output small-block in history. It would keep the record for nearly 40 years.

Chevrolet sold about 200 Corvette Z06s in 1963 and 1964. Then Chevrolet Performance retired the badge for nearly 40 years. Finally, in 2001, the Z06 returned. This time, it was a trim-level of the fifth-generation (C5) Corvette. 

For the reborn 2001 Corvette Z06, Chevrolet engineered a lightweight small-block dubbed the LS6. The 350 cubic-inch engine made 385 horsepower, finally dethroning the 1964 Corvette’s 327 as the highest horsepower small-block.

For the C6 Corvette Z06, Chevrolet engineers created a 427 cubic-inch small-block (7-liter) V8. Released in 2006, the engine was the largest small-block V8 in history. It made 505 horsepower.

Then, to catch up to the Hellcat, the C7 Corvette Z06 went supercharged. Chevrolet’s 2015 Z06 came with a 376 cubic-inch (6.2-liter) turbocharged V8 that made 650 horsepower. 

But the Corvette Z06 has always been an agile track car, not a drag-racer. So many fans protested the supercharger. Chevrolet Performance began to wonder if there was another way. The result was the 2023 Corvette Z06 V8.

The 2023 Corvette Z06 V8 (the LT6) completely destroys records with 670 naturally-aspirated horsepower

When the C8 Corvette went mid-engine, the Z06 team went back to the basics. Tadge Juechter, Corvette Executive Chief Engineer, revealed that they were drawn to “the immediate response, lightweight, visceral feel of a naturally aspirated engine.” But he admitted that they had to “exceed the horsepower of the prior generation supercharged Z06.” So for inspiration, the engineers looked to mid-engine Ferraris.

Several exotic car manufacturers build what is called a flat-plane crankshaft engine. While most V8 engines fire every 90 degrees, and most V6 and V12 engines fire every 60 degrees, the older flat-plane crankshaft design fires every 180 degrees. This is because the two banks of cylinders function as separate engines taking turns. As a result, these engines suffer from increased vibration. But with modern materials, they can rev to higher RPMs than most engines.

With the 2023 Corvette Z06 V8, Chevrolet again broke records. The performance division hand-built the world’s largest flat-plane crank engine. The resulting powerplant returns to Corvette’s roots: it is an all-new 5.5-liter V8.

2023 Corvette Z06 V8: return of the small-block Chevy V8

The 2023 Corvette Z06 V8 is an all-new small-block powerplant, somewhere in the ballpark of 330 cubic inches. This engine only makes 460 lb-ft of torque. But it can also make 670 horsepower. And it redlines at 8,600 RPMs. Just as importantly, it can reach its redline in the blink of an eye. The lightweight flat-plane crank, forged aluminum pistons, and titanium connecting rods keep the LT6’s rotating mass low. With a low rotating mass, the engine can spin faster and build RPMs quicker.

Cindy Molnar is a vehicle performance engineer with Chevrolet Performance Cars. She says of the 2023 Corvette Z06, “It makes power the whole way up. Even when you’re up in those higher RPM ranges.” The result is a supercar that pulls hard while revving over 8,000 RPMs.

Juechter says the LT6 is “by far the quickest spinning engine we’ve ever done.” He revealed, “The only way you do that is to have extremely precise manufacturing.” Juechter concluded, “The manufacturing tolerances in this engine are race car tight.”

Trained Chevrolet craftspeople are the force behind that precise manufacturing. Each LT6 Z06 engine wears a nameplate that reads “handcrafted by” and the signature of a technician at the Kentucky plant.

Conclusion

An all-new small-block V8 powers the 2023 Corvette Z06. Its displacement is a callback to the original 327 that set records in the very first Z06. At the same time, this new small-block harnesses exotic car technology to break the naturally-aspirated horsepower record, yet again.