Hennessey is building three 800kW+ Helephant-powered Mammoth 6×6 trucks

Mammoth 6x6 from Hennessey

Hennessey has decided to add an extra axle to the already mental 2021 Ram TRX and says it’ll be its most powerful truck ever. Meet the Mammoth 6×6.

The most powerful truck in its 29-year history. That’s what Hennessey Performance Engineering is saying about its extremely limited run (only three will be built) of 6×6 conversions of the 2021 Ram TRX, and it’s called the Mammoth 6×6.

As we’ve written about already, the 2021 Ram TRX is pretty nuts with its bespoke suspension and Hellcat engine. But that ain’t enough for Hennessey which has announced it’ll add an extra axle and bin the Hellcat engine for a Hellephant engine. Yeah, a Hellephant.

The Hellcat engine makes more than 500kW, but Hennessey’s bespoke 7.0-litre Hellephant engine will smash out more than 800kW. Hennessey founder and boss, John Hennessey, said: “Mammoth 6X6 powered by a 1200hp Hellephant motor is just a completely ridiculous idea, which is exactly why we are doing this. We are only going to build three examples which will likely make this the most exclusive and most expensive truck we’ve ever built.”

Beyond the bonkers engine and 6×6 conversion, the Mammoth 6×6 will get a new bed, upgraded off-road suspension, bespoke interior, new front and rear bumpers, LED lights and more. It’ll be available to order from 4 September with the price starting at $682,000.

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Isaac Bober has been writing about cars and 4x4s for more than 20 years, has worked on some of the country's biggest motoring magazines (remember what they were?), and launched Practical Motoring. Now he's back, back again... to share dad jokes and much more.