The new Camaro ZL1 is extremely impressive right off the showroom floor, running an 11-second quarter mile, pushing around 650 horsepower and 650lb-ft of torque. Its the fastest Camaro to date but, of course, that doesn’t stop Hennessey from tweaking it and making it even faster than before.

The HPE850 is a mid-grade upgrade from the team over at Hennessey Performance, lifting that already impressive horsepower number up to a whopping 858. Basically, the pretty short list of included upgrades are; high flow heads, a custom cam, long-tube headers, an intake, exhaust, and a custom tune. The stock transmission and torque converter are left alone.

The package is available for either factory automatic or manual transmission equipped vehicles. The manual ZL1 with the HPE850 pushes 735 horsepower and 706lb-ft of torque to the wheels–Of course, the automatic is slightly less due to driveline loss, but it still looks pretty insane if you ask us.

Hennessey just recently posted a new video, showing the HPE850 upgrade in action on a 10-speed ZL1. It shows a mean burnout, a pretty hard launch, and the car’s very first test run down the quarter mile. When fitted with 20-inch drag radials, like in the video, the 10-speed HPE850 ZL1 runs a 10.54-second quarter mile with a trap speed of 131.85 mph.

The upgrade costs $23,950 on top of the price of a new ZL1, coming in at around $87k. Sure, Hennessey’s creations are pretty pricey– but where else can you get a warrantied, 10-second, 858-horsepower Camaro?