A 1987 Ford Sierra Cosworth RS500 in Black showing 5,200 miles has sold for almost £600,000 at auction, setting a new world record for Sierra Cosworth RS500 prices. The RS500, with just 5,192 miles on the clock, went for £596,250 at the Silverstone Auctions Race Retro sale.

Described as ‘perhaps the finest example of Ford’s most desired Cosworth ever’, buyers clearly agreed with the marketing and frantic bidding ensued, with the car eventually selling for almost four times its pre-sale guide of £150-£180k.

Why are Ford Sierra Cosworth RS500 prices rising?

The RS500 Cosworth was announced at Geneva in 1987. Aston Martin Tickford was given the job of converting the road cars to RS500 specification. The racing version proved incredibly successful and the car won race series all over the world.

The rear-wheel drive (right-hand drive only) RS500 race car could produce a reliable 500bhp, but road car versions were limited to 224bhp. Despite a modest power increase on paper, there were extensive revisions to the standard Cosworth YB engine. A Garrett T31 turbo was installed with a larger intercooler and induction system. Twin fuel injectors in each cylinder, pressurised oil-cooled pistons and larger oil and water pumps helped the reliability and pace of the race car. The brakes were also uprated.

External changes were subtle, with a front splitter, additional cooling vents and a second tailgate spoiler added. A gurney flap was fitted to the ‘whale tail’ rear wing and RS500 decals were fitted as standard.

Performance was not much better than the standard Cosworth; the RS500 could reach 62mph in 6.2sec and achieve 153mph, compared to the 6.8sec and 149.5mph of the standard car. However, the relatively low asking price of £19,950 for a handmade, low volume RS special compared to £15,950 for the standard RS Cosworth meant that all 500 units sold fairly quickly. Their rarity and reputation as the ultimate British blue-collar supercar makes them valuable today.

Ford Sierra Cosworth RS500 prices

Previous highest Ford Sierra Cosworth RS500 prices

The previous record price for a Ford Sierra Cosworth RS500 was £132,750, which was paid last year at Silverstone for a car with 9k miles. Recent Cosworth valuations for cars with up to 30k miles have all been circa this figure, but it is clear that the market for low-mileage examples has significant potential.

While the 5k-mile car was said to be offered by a ‘knowledgeable and particularly fastidious enthusiast’, this describes most of the RS500 owners I deal with. The car had been regularly serviced and maintained by Southampton-based classic Ford specialist Tremona Garage, including a complete recommissioning service during 2022.

The selling price of this car may lead to a rise in supply of higher-mileage examples at auction through to Q3 2023. Anyone with an RS500 Cosworth insurance valuation should be very aware of this new benchmark and update their valuation accordingly!

Photo by Silverstone Auctions