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Here's the Story of the Iconic IROC Racing Porsches of the 1970s

The first International Race of Champions (IROC) was held at Riverside International Raceway in California in 1973, when the Porsche 911 was only nine years old. In the groundbreaking competition, the world’s top racing drivers all drove 911 Carrera RSRs, identical except for their candy-colored paint jobs—and extremely valuable today.

IROC, comprised of four races in all at Riverside and the Daytona International Speedway road course in the fall and winter of 1973–74, featured the likes of Emerson Fittipaldi (Formula 1), AJ Foyt (Indy), Richard Petty (NASCAR), Al Unser (Indy), and George Follmer (Can-Am). The RSR had already made headlines by winning the 24 Hours of Daytona earlier in 1973, followed by the Targa Florio.

The epic event is chronicled in a cool new book from Motorbooks, The IROC Porsches: The International Race of Champions, Porsche’s 911 RSR, and the Men Who Raced Them, by Matt Stone, set to be released later this month and now available for pre-order on Amazon. "The drivers’ incentive to compete was manifold, first being to demonstrate the talents and abilities of their own particular brands of racing," as the publisher puts it, though "not to be understated was the draw of significant payout to winners."

Consummate Porsche racer Mark Donohue won the first year’s championship, pocketing $54,000 USD (more than $300,000 USD in today's dollars). Only the top six finishing drivers competed in all four races, which became "one of the most interesting and storied episodes in 911 racing history," helping to cement the iconic sports car's reputation. 

"The premise was simple and brilliant," Motorbooks notes. "Put the world's best racing drivers in identical cars and the series winner could legitimately claim to be the 'best in the world.'" Former racing driver, business mogul, and racing team owner Roger Penske, "the original force behind the series," worked directly with the Porsche factory in Stuttgart to get the special IROC Porsches designed and built.

While the IROC series would carry on for several decades, it would never again feature Porsches or field such a diverse selection of race drivers, making that first season "truly lighting in a bottle." Pick up a copy of the book here for the full story, and the 200 glorious photographs.