Ariel has released the first picture and details of the Atom V8 engine.
The unit develops 500 bhp, giving the car a power-to-weight ratio of 1000bhp per tonne.
Featuring a compact 75 degree V arrangement with four valves per cylinder and a unique cam drive arrangement the engine is very compact and weighs just 90 kilos.
Power is driven through a Sadev six-speed sequential gearbox operated through a manual shift, although Ariel is looking at a paddle-shift option.
The car will feature adjustable traction and launch control as well as programmable settings for different conditions.
There is a new suspension and brakes specific to the 500.
The Atom 500 will be limited to 25 cars, with half already sold, and the price is yet to be set.
"Our aim is to build the ultimate road legal track day car," said Simon Saunders, director of Ariel. "Our motto has always been, 'go fast, have fun' and the Atom V8 is certainly going to do that."
The Atom 500 will have a 0-60mph time of under 2.5 seconds and 100mph arrives in less than six.