The final build slot for the last-ever V8-powered Dodge Challenger has raised $US700,000 ($AU1.06 million) for a children’s charity at an auction in the US – after the muscle car was sold twice in an unexpected twist.

The Challenger SRT Demon 170 is the last of seven limited-edition Challenger coupes and Charger sedans models released to celebrate Dodge ending production of its V8 ‘Hemi’ engines, before the next-generation models sedan downsize to six-cylinder or electric propulsion.

Dodge offered the final build slot for the Challenger SRT Demon 170 at a Barrett-Jackson auction in Las Vegas, announcing it would donate 100 per cent of the hammer price to Kristi House – a non-profit organisation focused on eradicating child abuse and child sex trafficking.

Bidding for the final Dodge Challenger SRT Demon 170 reached $US400,000 ($AU605,000) and the auction was presumed over – before a shock twist saw the winning bidder donate the car back, pledging his bid to the children’s charity.

After the auction was restarted, a final winning bid of $US300,000 ($AU454,000) was placed – resulting in a total donation of $US700,000 ($AU1.06 million) to Kristi House.

While the Dodge Challenger SRT Demon 170 normally retails for $US100,361 ($AU151,800), the drag car for the road’s entire allocation sold out shortly after it was revealed in March.

Dodge has previously said it plans to build 3300 Challenger SRT Demon 170s – 3000 for the US and 300 for Canada – though production of the limited-run model will come to an end on 31 December 2023, irrespective of how many have been produced.

The unnamed buyer of the final Dodge Challenger SRT Demon 170 can select their own paint and options, while Hollywood actress Nicole Kidman – who helped auction the car – offered both winning bidders tickets to her husband (and fellow Australian) Keith Urban’s upcoming concerts.

As previously reported, the Dodge Challenger SRT Demon 170 is powered by a supercharged 6.2-litre V8, capable of producing up to 764kW – or 1025 horsepower – and 1281Nm when running on E85 ethanol-blended fuel.

The muscle car’s ability to complete a 400 metre drag strip run in 8.91 seconds at 151mph (243km/h) will result in the National Hot Rod Association (NHRA) issuing a violation letter to drivers who take the vehicle to events run by the organisation – until owners fit it with a roll cage and parachute.

As reported in August 2022, flagship variants of Dodge’s next-generation Challenger and Charger are expected to be powered by a new 3.0-litre twin-turbo six-cylinder petrol engine, though certain versions of the muscle cars will also adopt electric motors – as previewed by the Dodge Charger Daytona SRT Concept.