Hennessey is achieving 643 hp in a twin-turbo C8 Chevrolet Corvette V8 in the early stages of development.

It took Hennessey Performance Engineering 30 hours to disassemble the 2020 Chevrolet Corvette, install the turbos, and put it back together.

Unsurprisingly, the twin-turbo C8 Corvette is not yet ready to be sold to buyers. The engine doesn't have an intercooler, and Hennessey hasn't even cracked the code for GM's new electrical architecture to reprogram the ECU.

"This is just the beginning, it's our own car, and we're doing research and development," founder and CEO John Hennessey told Motor Authority.

On Monday, the engine was dyno-tested on the DynoJet, producing 643 hp and 570 lb-ft of torque at the wheels at just 5 psi of boost HPE's baseline tests on a stock car recorded a maximum output of 466 hp and maximum torque of 451 lb-ft. HPE plans to offer a 1200-hp version of the C8, which Hennessy says will have a supercharger of 18-20 psi.

Hennessy received an orange C8 Corvette in Detroit on June 13. He and his daughter Emma drove the car to Performance Outfitters headquarters in Texas for baseline testing, after which Hennessy's team disassembled the car.

On Friday, the orange C8 came to life, equipped with two 62 mm Precision turbines and two supercharger valves connected to a throttle body mounted behind the catalytic converter. Both turbines are oil-cooled and have twin sump pumps that feed the exhaust to the engine.

The system has no intercooling. Instead, it is injected with methanol to prevent overheating; HPE is considering installing an intercooler. With the current layout, space to install an intercooler is limited and does not reduce trunk space, something Hennessey does not want.

Hennessey told Motor Authority that his team is currently looking at aftermarket solutions for the engine management system, although customization of the stock ECU is not possible. He noted that it took a year to bring a solution to market for the C7, adding that "hopefully it won't take a year."

According to Hennessy, when the turbocharged C8 was first started, no codes, errors or engine performance indicators appeared. The computer seems happy with the turbocharger's performance," Hennessy said. Hennessy said the Check Engine light came on when the front wheel speed sensors were removed to put the car on the dyno.

The orange C8s will be used for research and development of future modifications; according to Hennessy, delivery of modified C8s to customers is not scheduled for at least six months, and all will be equipped with intercoolers and full plumbing.