Hennessey’s 1,200-horsepower Corvette ZR1 upgrade will show up a Demon by running a quarter-mile drag race in under 9 seconds.

We knew several months ago that Hennessey's 1,200-hp upgrade for the C7-gen Chevy Corvette ZR1 would be fast, but we didn't know how fast because Hennessey didn't post any numbers. That likely has more to do with the car still being tested than any caginess on the part of Hennessey.

Now, thanks to Hennessey taking their ludicrous Corvette to a drag strip, we have a pretty good idea of just how fast this mean machine is.

But first, a reminder of just how much work went into building Hennessey's monstrous 'Vette. There are enough upgrades here to make you question just how much of the engine is still factory and how much is due to Hennessey's fiddling. There's a new high-flow throttle body, upper and lower pulleys, a custom camshaft, ported cylinder headers, new springs, intakes, valves, retainers, lifters, and pushrods, long-tube stainless steel headers, and new high-flow catalytic converters.

To keep it from melting, the exhaust midpipes have been upgraded to stainless steel, while the 8-speed automatic transmission has been strengthened to handle 1,200 horsepower and 1,066 lb-ft of torque. The manual version doesn’t need strengthening, but wouldn’t be nearly as fast down the drag strip.

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For their quarter-mile test, Hennessey gave their HPE1200 'Vette E85 racing fuel and a set of MT drag radials wrapped around 18-inch rear wheels. The track was definitely prepared for a proper drag race, but conditions were hardly ideal at 102 degrees F (that's 39 degrees C). You can see Hennessey used several industrial fans to keep the ZR1 cool in between runs.

It takes a lot to break the 9-second barrier, but Hennessey did it by running 8.97 seconds at 156.25 mph. That’s fast enough that the front tires left the ground off the line.

Check out the video above to see this car move faster than any other Corvette out there.

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