The Group A competitive spec Sierra Cosworth RS500 is back

30th October 2021, 7:18am
3 min read
The Group A competitive spec Sierra Cosworth RS500 is back
  • Three 575bhp cars to be built by CNC Motorsport AWS

CNC Motorsport AWS, the British racing vehicle manufacturer, has announced plans to build a set of Sierra Cosworth RS500 Group A race cars in the specification from 1990 Andy Rouse Engineering. 

CNC has had a new three-door Sierra bodyshell, known as a 909, carefully stored since the late 1980s, which sparked the idea for the new models.

The turbocharged four-cylinder Cosworth YB engine will be an original specification fresh build, producing upwards of 575bhp thanks to a Proflex Advanced fuel system. It'll be mated to a Getrag five-speed manual transmission, which will drive the rear wheels through a nine-inch viscous differential.


The brake system, interior instruments, and a special Andy Rouse Engineering build plate are all included, with each of the three cars arriving in a blank white finish, ready to be customised with fresh liveries. Each car will start at £185,000 and will not be road legal.

The three prototypes will be made with an authentic Ford Sierra Cosworth body shell, with the first one utilising an entirely unused '909 competition' shell that has been in storage since its production in the 1980s. After completion, all cars have FIA Historic Technical Passports, roll cage certificates, and a modern fuel cell, making them race-ready.

These aspects will be enhanced with the installation of new parts, including parts of the front suspension, side exhaust system, and unique roll cage, all manufactured to Andy Rouse Engineering specifications and compliant with Motorsport UK standards.

The three cars will be created in conjunction with Andy Rouse Engineering and will compete in classic racing series such as Motor Racing Legends and the Silverstone Classic.


These cars are fun to drive, easy to maintain, and much cheaper than Super Touring cars, so we expect to see more of these re-builds if the Sierra Cosworth RS500 generates enough interest.

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Written by Raymond Burrett

Raymond is the quintessential car enthusiast. Motorsports and sports-cars have played a prominent role since a young age. He can now be found tinkering with his Japanese sports cars, at local car meets or out on a track-day.