Hennessey Performance Engineering (HPE) is adding a modified 2021 Dodge Durango SRT Hellcat to its lineup. As with the Dodge's Jeep Grand Cherokee Trackhawk sibling, Hennessey will offer 1,012-horsepower and 1,200-horsepower versions. However, the 1,200-hp option for both the Dodge and Jeep is an off-menu item.

The HPE1000 upgrade for the Durango's 6.2-liter supercharged V-8 yields the aforementioned four-digit horsepower figure, plus 969 pound-feet of torque. Those are increases of 302 hp and 324 lb-ft of torque over the stock Durango Hellcat. That's achieved with upgrades to the air-induction system, exhaust system, and fuel injectors, plus a bigger supercharger.

With the extra power, Hennessey claims the Durango will do the 0-60 mph run in 2.8 seconds, and run the quarter mile in 10.8 seconds at 126 mph. Dodge quotes a 0-60 mph run of 3.5 seconds, and a quarter-mile sprint of 11.5 seconds at 118 mph for the stock Durango Hellcat.

2018 Hennessey HPE1200 Jeep Grand Cherokee Trackhawk

2018 Hennessey HPE1200 Jeep Grand Cherokee Trackhawk

A 1,200-hp upgrade was previously listed as an option for the Jeep Grand Cherokee Trackhawk (which uses the same Hellcat engine) on Hennessey's website. It's now gone, and there is no mention of a 1,200-hp Durango on the site. Much more work is needed to get that extra power, so customers must now request the upgrade for either SUV.

“We are more efficient at building the 1,012-horsepower deal. The 1,200-horsepower deal takes removing the engine and upgrading the internals of the motor. It takes several months to do all that. We do still offer the 1,200-horsepower (option), but I might be willing to do one a month," founder John Hennessey told Motor Authority. Hennessey also noted HPE builds 15 vehicles a week and called the 1,200-hp Durango a "limited availability kind of thing."

Customers can expect an HPE1000 Trackhawk or Hellcat to be completed in about six weeks, but they'll have to wait three to four months for delivery of the 1,200-hp version of either SUV, Hennessey said. Even the HPE1000 Durango will be hard to get, however, as the company is limiting production to 50 units.