Home Lamborghini Miura ex-Follmer / Donohue Riverside-winning 1973 Porsche 911 3.0 Carrera RSR IROC — Supercar Nostalgia

ex-Follmer / Donohue Riverside-winning 1973 Porsche 911 3.0 Carrera RSR IROC — Supercar Nostalgia

ex-Follmer / Donohue Riverside-winning 1973 Porsche 911 3.0 Carrera RSR IROC — Supercar Nostalgia


Reprinted below is The Octane Collection’s description for this sensational 911 RSR:


International Race of Champions (IROC) was a North American auto racing competition, promoted as an equivalent of an American All-Star Game or The Masters. Despite its name, the IROC was primarily associated with North American oval-racing culture. Drivers raced identically-prepared stock cars set up by a single team of mechanics in an effort to make the race purely a test of driver ability.

The IROC was conceptualized by Les Richter – as an ex-NFL star, he knew something about TV and sports – along with Roger Penske and partner Mike Phelps. Penske ordered 15 rainbow-hued cars from the factory, which were delivered to Riverside in late 1973 for the first of four title rounds, which culminated at Daytona the following February. Mark Donohue was the first driver to win the championship with 3 victories from 4 starts.

Few people realise that the IROC RSRs from 1973 were built specifically for Roger Penske, Porsche’s motorsport wizards back in Weissach applying a raft of special racing features to each from the forthcoming 1974 model. These included the extended ‘whale-tail’ spoiler to replace the ‘ducktail’, flared wheel arches and bumpers to accommodate wider Fuchs wheels, and an updated 3.0-litre twin-ignition flat-six.

They were placed under the administration of Penske Racing, Inc. lieutenant Jay Signore, the longest-enduring figure of any kind in IROC history. He recalled, “In the early days, I was mostly involved back at the shop, having managed Penske Racing, and we were trying hardest to make the cars equal. We had the test cars delivered to our Indy car shop in Reading, where Al Holbert did the chassis setup, and sent the information to Germany. After the Riverside race, we took the drivetrains out of them and shipped them to Germany, where Porsche tuned them for the Daytona finals and shipped them back. All the engines were dyno’d there. Holbert did the setups, and Follmer was one of the development drivers.”

The IROC Porsches relates one of the most interesting and storied episodes in 911 racing history. The premier season of the International Race of Champions series was founded around purpose-built, virtually identical racing cars to be driven by racing greats from IndyCar, Formula 1, NASCAR and other international racing series. The premise was simple and brilliant: put the worlds best racing drivers in identical cars and the series winner could claim best in the world. In the interests of a level playing field, no one driver would have the same car in each race with names drawn out of a hat before practice.

The depth of talent and breadth of racing disciplines embodied in the series was stunning: Emerson Fittipaldi (Formula 1), AJ Foyt (Indy), Richard Petty (NASCAR), Bobby Unser (Indy), George Follmer (Can-Am) alongside Mark Donohue, Peter Revson, Denny Hulme, Roger McCluskey, David Pearson, Gordon Johncock and Bobby Allison.

Drivers’ incentive to compete was first being to demonstrate the talents and abilities of their own particular brands of racing but also the draw of significant pay out to winners. Consummate Porsche racer Mark Donohue won the first year’s championship.


1 of 15 Original supplied 1973 IROC race cars. Original Colour – Black 041, Rebuilt 911/72 IROC spec ‘High Butterfly’ Engine, Genuine Fuchs wheels, Fahrzeugbrief with German road registration, Fire extinguisher, Race Harnesses.


For 1973, FiA Group 4 homologation and special GT’s took on a new form – enter the Porsche 911 3.0 RSR. With a larger front air dam, wider steel arches and the renowned whale tail rear spoiler, 15 of these fantastic machines would be ordered for a new series in the US by Roger Penske – the International Race of Champions.

Here we have not only an original IROC entrant, Chassis 0124 is the most successful chassis to have raced in the series. Having been restored by top classic restoration and race specialists – Karosserie Stimming (who include Walter Rohrl amongst their driving team) the car is in fabulous condition having been part of a significant Porsche collection.

The paintwork presents beautifully in a uniform and consistent hue all around the car, not often the case with track optimised examples. With only one or two light chips to the rear arches to report, the front air dam and rear wing present as the should alongside excellent fit and finish of all trims and rubbers.


The attention to period correct detail on board is second-to-none, with only a front passenger seat and extinguisher plumbing setting the car apart from the paddock at Riverside in 1973. The cabin has been sympathetically updated with safety in mind but pleasingly retains its character and originality where possible – dials, switch gear and controls remain untouched finished with a magnificent 3.0 RS steering wheel alongside the IROC gearshift sticker. The Recaro seats, barely used and in excellent order, are equipped with 4 point harnesses.

By using GRP panels, plastic side windows and stripping out all but the most essential items of interior trim, the RSR barely tipped the scales at 900kgs.


The pace in development from RS to RSR over a 2 year period involved significant work to the engine – capacity increased from an initial 2.7 to 2.8 then 3.0 with special ‘high butterfly’ fuel injection, bigger valves, higher compression and racing cams producing a reliable 300 horsepower at 8,000 rpm. For the series finale at Daytona, and having had the engines sent back to Germany, the cars were dyno’d at an average of 316hp.

Having been rebuilt to exacting spec, the IROC specification engine is simply a work of art.


The Fuchs wheel design is symbolic amongst classic Porsche variants and original set fitted do not disappoint with huge 11 inch rears and 9 inch on the front. All four corners matched to period Michelin rubber.

Supplied with finned 4 pot brake calipers and discs found on the iconic 917, the braking system also features dual master cylinders to ensure fantastic stopping power.


Initially supplied as a spare car alongside 0040 Birch Green and 0042 Jade Green, 0124 Black did not compete in Race 1 of the inaugural IROC series.

However, as is the nature of one make series with cars suffering damage, it would not be long before the car took the grid with George Follmer in Race 2.

Follmer would start 9th and battle through the field to secure the win – a debut victory for 0124! For Race 3, Mark Donohue would start from pole by virtue of a DNF in Race 2. The All American legend would dominate from lights to flag with a resounding second victory and in doing so ensured a 100% winning record for 0124. Given the car did not compete in Race 1 or the series finale at Daytona, it won the only 2 races it ran in and was the only ever IROC to win two races.

The most successful IROC RSR would then be sold to prominent racer Al Holbert, who later ran Porsche North America’s Motorsports Division.

Holbert campaigned 0124 successfully in the 1974 IMSA Camel GT and Trans Am series;

Daytona: Peter Revson 2nd
– Road Atlanta: A.Holbert 1st
– Lime Rock TA: A.Holbert 1st
– Lacuna Seca: A.Holbert 1st race DNF, 2nd Race 4th
– Road America: A.Holbert 3rd
– Ontario: A.Holbert 1st Race 31st, 2nd Race 4th
– Mid-Ohio: Peter Gregg & A.Holbert 1st
– Road America: A.Holbert 3rd
– Charlotte: A.Holbert & E.Forbes-Robinson 6th
– Daytona: A.Holbert 2nd

Unfortunately a testing accident at Mid Ohio brought an early end to 0124’s racing career before leading Porsche aficionado and author John Starkey purchased the car from Holbert’s workshops in 2007. The following year, the car was sold to Ulrich Schumacher who was keen to return the rare RSR to its original IROC livery and specification. In 2009, Schumacher instructed Karosserie Stimming, one of the most respected German Porsche restoration specialists, to bring the car back to it’s former glory.

The car still has the correct 911/72 engine (6840026) which was subject to a thorough rebuild alongside the gearbox. All racing history and movements in the US are well documented and also feature in the Matt Stone book – The IROC Porsches with original Fahrzeugbrief, road registration papers and restoration details included in the history file.

As a company famed for it’s racing DNA, Porsche Motorsport does not come any purer than this. Given the iconic badge, the hall of fame driving roster and incredible success this car achieved in period; Chassis 0124 has to be one of the most significant racing 911’s in existence.

For more information visit The Octane Collection website at: https://www.theoctanecollection.com/



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