Earlier this year, Hennessey uncovered a mental Chevrolet Corvette ZR1, with a whopping 1,200 horsepower. Now, a different example, equipped with the same HPE1200 package, has been strapped to the dyno.

Putting its money where its mouth is, the immensely powerful car demonstrated that it produces 1,139 horsepower at the wheels, and 994 pound-feet (1,348 Nm) of torque, when running on E85 gasoline, at a 24 psi boost pressure. The official output released by the tuner at the crank is 1,200 hp and 1,066 lb-ft (1,445 Nm).

Also Watch: Hennessey’s 1,000 HP Corvette ZR1 Runs 1/4 Mile In Under 10 Seconds

When they announced the preliminary info, Hennessey said that it’s achievable on race gas. With 93 octane fuel in the tank, the 6.2-liter, supercharged V8 is supposed to churn out 1,100 horsepower. So, after seeing it on the dyno in the latest clip, it’s clear that they have underrated it, as the new internals and upgraded parts have significantly transformed the unit.

The best part about this project is that, aside from a few stickers and badges, the rest of the car retains the stock look. The only thing this tuned ‘Vette ZR1 needs right now is to be subjected to acceleration tests, but before Hennessey decides to unleash it on tarmac, let’s watch it in the lab.