Putting it on the dyno is the only way to find out...
In a world increasingly preoccupied with squeezing every ounce of efficiency out of the internal combustion engine, redefining "normal" to conjure downsizing and turbocharging, low-viscosity lubricants, lighter-duty internals, it's oddly refreshing to know that Mopar's brutish "Hellephant" crate engine exists. Displacing a whopping 426 cubic inches - or 7.0 liters - with forged pistons, a high-lift cam, and a massive 3.0-liter twin-screw supercharger, the Hellephant is the 1,000-horsepower answer to the question: "What happens when the engineers take things too far?"
Now, we've seen the Hellephant in action and found out if it can live up to the 1,000 hp claims on its first dyno run.
The folks over at YouTube channel Demonology were among the lucky select few that were able to secure an example of the 1,000-horsepower Hellephant, and this week, they did the motoring world a favor by putting it on the dynamometer, for a proper, objective look at how much power it really makes.
We won't drag it out; installed in their 2018 Dodge Challenger SRT Demon, the 426 Hellephant peaked at a tire-torturing 944 horsepower at the rear wheels, with 877 lb-ft of torque. With the standard assumption of 15% drivetrain loss between the crank and the wheels, that would put the Hellephant's peak output closer to 1,100 horsepower, although there are some caveats.
The biggest caveat is that the car was running E-40 at the time of the test - that is, a blend of 40 percent ethanol with 60 percent gasoline. Ethanol has a much higher octane rating than pump gas, permitting more spark advance and, thus, more power. But beside that, there's also no knowing precisely what percentage of the engine's torque is being lost through this Demon's drivetrain. That 15% drivetrain loss is just a rough average, and it varies quite a lot from car to car.
So, we still don't know for certain what the Mopar 426 Hellephant crate motor puts out, but at the very least, we can say with some confidence that it doesn't seem overrated from the factory. Not in the least.