Hennessey Unleashes the MAMMOTH 700 RAM RHO

When the Ram 1500 TRX left the lineup, the 2025 Ram 1500 RHO stepped up to take the spotlight. Powered by Stellantis’ twin-turbocharged 3.0-liter HURRICANE I6 High-Output (H/O) engine, the RHO immediately proved that six cylinders could deliver serious full-size truck performance. With 540 horsepower out of the box, it has the muscle to play in the same league as the V8s of old.

But for enthusiasts who want something even more extreme, Hennessey Performance Engineering (HPE) has unleashed the MAMMOTH 700 Ram RHO, a package designed to turn Ram’s new halo truck into a true monster.

More Power from the HURRICANE I6 H/O – 

The heart of the MAMMOTH 700 is the RHO’s HURRICANE I6 H/O. In factory form, it’s already impressive, but Hennessey takes it to the next level. By increasing boost pressure, upgrading the stainless-steel exhaust, and recalibrating the engine management software, output jumps to 700 horsepower. Each truck is dyno-tested, calibrated, and then road-tested for up to 500 miles before delivery. The upgrades don’t just provide more speed—they’re engineered to maintain full drivability and retain the factory driving modes that make the RHO such a balanced performer.

Ready for the Trails – 

While the MAMMOTH 700 can easily dominate on pavement, Hennessey builds it to shine off-road as well. The package lifts the truck three inches, adds a front and rear leveling kit, and bolts on aggressive 37-inch off-road tires mounted on 20-inch Hennessey wheels. A custom front bumper integrates LED lighting and sensor compatibility, while a heavy-duty skid plate provides protection on the trails. Out back, a matching Hennessey bumper ensures both durability and style. Together, these upgrades transform the RHO into an even more capable off-road weapon.

Confidence in Stopping Power – 

More horsepower and larger wheels demand stronger brakes. To meet that need, Hennessey offers an optional 6-piston performance brake kit that includes stainless-steel braided lines, high-temp pads, and heavy-duty rotors. These upgrades give the truck the stopping power it needs whether towing, trail running, or opening up the Hurricane engine on wide-open roads.

Everyday Convenience – 

Hennessey doesn’t forget about daily usability. Electronic fold-out steps make it easier to get into the lifted truck, while Hennessey-branded all-weather floor mats add durability inside the cabin. These little touches make the MAMMOTH 700 as practical as it is extreme.

Complete Upgrade List – 

To make it clear, here’s what comes standard with the MAMMOTH 700 Ram RHO package:

• Increased boost pressure

• Upgraded stainless-steel exhaust system

• Engine management software upgrade

• All necessary gaskets and fluids

• Professional installation

• Dyno calibration and up to 500 miles of road testing

• Hennessey® and MAMMOTH® 700 exterior badging

• Serial-numbered engine bay plaque

• 3-year / 36,000-mile limited warranty

• Hennessey® off-road front bumper with sensor integration

• Bumper-mounted 32-inch LED light bar

• 5-inch round center LED lights

• 3-inch corner LED lights

• Custom Hennessey skid plate

• Hennessey® off-road rear bumper

• Front suspension leveling kit

• 3-inch overall lift

• Powered electronic fold-out steps

• Hennessey all-weather floor mats

• Optional six-piston performance brake kit with stainless-steel lines, rotors, and high-temp pads

• 20-inch Hennessey wheels with 37-inch off-road tires

Texas-Built and Backed by Warranty – 

Every MAMMOTH 700 is hand-built at Hennessey’s Sealy, Texas headquarters. Trucks undergo extensive dyno sessions, lab work, and proving ground testing before final sign-off. Each build is covered by a 3-year/36,000-mile warranty, giving customers peace of mind along with the performance boost. Buyers even have the option to take delivery at Hennessey’s Pennzoil Proving Ground, making the experience as memorable as the truck itself.

The Price of Going Mammoth – 

The MAMMOTH 700 package adds about $70,000 on top of the cost of a Ram 1500 RHO. With the truck itself starting around the same figure, the total pushes into six-figure territory. 

Final Thoughts – 

The Ram 1500 RHO already proved that Stellantis’ HURRICANE I6 H/O engine could carry the torch for high-performance pickups. With Hennessey’s MAMMOTH 700 treatment, the RHO becomes a truck with the muscle of a supercar, the presence of a trophy rig, and the usability of a daily driver. It’s bold, it’s Texas-sized, and it’s built for those who think “stock” is just the starting point.