See how well the new HPE900 upgrade from Hennessey works on the McLaren 720S in this validation video.

Last month, we saw Hennessey take a perfectly fine McLaren 720S and do something horrible to it. They replaced the exhaust with a custom one, upgraded the air intakes, installed some blow-off valves on the factory twin-turbos, and re-tuned the ECU to handle all the new doodads and thingamabobs.

Then we saw it produce 809 rear-wheel horsepower, which is a lot. It’s certainly more than the 710 hp than the stock McLaren 720S makes at the crank, that’s for sure.

Now we get to see Alex from Hennessey validate this new beast on their test track. We typically see Alex performing these tests and are convinced that he’s a very good driver. He normally seems physically incapable of excitement--perhaps due to all the incredibly fast cars he gets to drive on the daily--but in the HPE900 McLaren 720S, he seems to genuinely smile for the first time in a very long time.

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Being able to do 50-160 mph in less time than it takes to blink would probably do that to even the most jaded of test drivers.

We also get to see the HPE900 perform a launch from a dig on a completely unprepped surface. Even though Alex was likely feathering the throttle just a bit to keep the 720S from spinning into the stratosphere, it still accomplished a very fast 0-60 time.

The new owner is sure to be very happy with his upgraded whip. But even better would be the HPE1000 upgrade that Hennessey now advertises on their website. This replaces the ECU with a Motec unit, adds stainless steel turbo headers, and upgrades the stock transmission to handle all the additional strain, pushing the power output to 1,000 crank horsepower.

We’ll have to wait for someone to buy such a beast before we can see it in action. But if they do, a reminder that Hennessey provides a 3-year, 36,000-mile warranty--usually. There’s no mention of it on the HPE1000 page, but surely that’s a mistake. Right?

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