Back in May 2024, the most famous tuner in Texas kicked off H850 Dark Horse production. Two months later, the Mustang GT also received this upgrade pack, which upgrades the 5.0-liter naturally aspirated Coyote V8 from 480 horsepower stock to 850 supercharged ponies.
That is more than Ford's very own S550-generation Mustang Shelby GT500 and quite likely more than the 800-plus-horsepower Mustang GTD for model year 2025. The H850 package is obviously centered around a twin-screw blower from Whipple Superchargers. On the manufacturer's website, said blower is $9,295.99 in Stage 1 flavor. Stage 2 retails at $9,995.99 sans the optional $599.99 dual pass heat exchanger and the $499.99 dual intercooler pump upgrade.
Whipple advertises up to 875 horsepower with a 112-millimeter throttle body and a 120-millimeter inlet. Hennessey didn't mention how much the H850 package costs for this application, but we do know that it's $24,950 excluding optional extras for the DH.
The declared 850 horsepower and 2015 Dodge Challenger SRT Hellcat-matching 650 pound-feet (881 Nm) of twist are delivered at 7,250 and 4,900 revolutions per minute, respectively. In addition to the blower, Hennessey's go-faster package further includes high-flow induction, upgraded injectors and pump, engine management calibration, chassis dyno tuning, and some road testing prior to customer delivery.
On the aesthetic level, you can easily tell an H850-equipped Mustang GT from bone-stock cars by means of Hennessey and H850 badging, H850 embroidered headrests for the front seats, and the serial-numbered plaque that beautifies the engine compartment. The car in the featured clip, for example, is #002.
Photo: Hennessey
While it's a pity the folks at Hennessey Performance Engineering did not retain the factory dual-throttle-body setup, the sound this fellow makes can only be described as decidedly muscular. The Coyote always sounded great, with the blower's whine only adding to the aural pleasure delivered by said V8.
Every build comes with a three-year/36,000-mile warranty, and those miles convert to just under 58,000 kilometers in the metric system. Hennessey didn't specify whether the H850 package is exclusive to GTs equipped with the 10R80 automatic or also compatible with the Getrag-supplied MT82 manual transmission.
In the Dark Horse's case, Hennesey does offer said package in combination with the Dark Horse-specific Tremec. However, the 10-speed automatic developed by Ford is quicker, helping the H850 Mustang Dark Horse hit 60 miles per hour (97 kilometers per hour) in 3.3 seconds compared to 3.7 seconds stock.
Hennessey tested the stock Dark Horse at the Pennzoil Proving Grounds, clocking a best of 12 seconds at 118.4 miles per hour (190.5 kilometers per hour) in the quarter fully stock. In upgraded from, the quarter-mile figures improved to 10.9 seconds at 133 miles per hour (214 kilometers per hour). Unfortunately, the Texas-based tuner hasn't published the numbers for the S650-gen Mustang GT with the H850 pack.
After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well. Full profile
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