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Porsche Index
Porsche – Porsche 911 3.0 Carrera RSR IROC – 1970s GT Racers – One Make Racers
Background
The inaugural International Race of Champions (IROC) was the brainchild of American industrialist and team owner, Roger Penske. The contest would pitch twelve of the world’s top Formula 1, NASCAR and Indy car drivers against one another in identical machinery over the course of three 30 lap heats at Riverside followed by a 25 lap grand finale at Daytona a few weeks later.
Penske commissioned Porsche to produce a batch of 15 identical 911s for the series, three of which would serve as practice hacks and T-cars.
Thanks to his excellent connections and a massive prize fund, Penske was able to attract a glittering array of drivers. From the world of Formula 1 came Emerson Fittipaldi, Denny Hulme and Peter Revson. NASCAR legends Richard Petty, Bobby Allison and David Pearson also took part along with Indy car drivers Bobby Unser, AJ Foyt, Gordon Johncock and Roger McCluskey. Mark Donohue and George Follmer signed up from Can-Am.
Each driver was assigned a car by virtue of a lottery system with seat adjustment the only modification permitted. Penske’s mechanics were given exclusive access to the cars during the race weekend and the entire field was collectively insured by Lloyds of London for what was reputedly the highest premium of all time.
After each 30 lap race, the drivers were required to change cars and the starting order for the next race was reversed according to the most recent finishing positions.
The first two heats took place after two days of practice on Saturday 27th October between qualifying sessions for that weekend’s Can-Am contest with each driver permitted two flying timed laps.
1973 Riverside Heat 1
Despite having been the only driver never to race at Riverside before, it was Emerson Fittipaldi that took pole followed by Donohue, Revson, Follmer, Pearson, Hulme, Unser, Foyt, Allison, Petty, Johncock and McCluskey.
However, both Fittipaldi and Follmer were made to start from the back of the grid because they they were late to the pre-race drivers meeting (Fittipaldi had been stuck in traffic and Follmer was delayed following Can-Am qualifying).
As a result, Mark Donohue was promoted to pole alongside Revson with Pearson and Hulme on the second row.
The start of Heat 1 saw Donohue squeeze ahead with Revson and Pearson in close pursuit followed by Unser, Follmer, Hulme and Foyt.
After half a dozen laps, the hard-charging Revson was passed by Pearson and Unser as his brakes began to fade. By this time, Fittipaldi had nearly caught up to sixth placed Hulme. Unfortunately though, on lap seven the Brazilian span off and damaged a fuel line which forced him out of the race.
All the remaining cars began to suffer brake fade during the final ten laps as the field had spaced out.
Second-placed Pearson’s car then started to smoke badly and he dropped down field which left Unser to claim second. Unser ultimately finished eight seconds behind Donohue who drove a typically well-judged race.
Revson was a few seconds further back to claim the final podium spot.
Despite a late spin, Follmer lost little time and was able to retain fourth from Hulme and Foyt while Petty was a long way back in seventh having struggled to adapt to the Porsche.
McCluskey was a distant eighth after spinning on Pearson’s oil.
Pearson finished ninth while Johncock was tenth; he had lost an entire lap for a pit stop to straighten out bodywork damage incurred following an off-track excursion while chasing down McCluskey.
Allison was classified eleventh after he ran into gearbox trouble and had had both front and rear windshields blow out.
Fittipaldi was the only non finisher.
1973 Riverside Heat 2
Later that day, Heat 2 took place with a reverse grid.
Fittipaldi started from pole followed by Allison, Johncock, Pearson, McCluskey, Petty, Foyt, Hulme, Follmer, Revson, Unser and Donohue.
The Brazilian initially retained his lead but on lap two Allison and Pearson barged through demoting Emmo to third. A few laps later, Pearson forced his way past Allison to assume the lead and the front three broke away from the rest of the field.
Just before mid-distance, Fittipaldi regained second spot from Allison and then re-took the lead from Pearson.
Meanwhile, Follmer had stormed up the field from ninth on the grid and soon went passed Fittipaldi to head the field. Pearson in turn re-took second from Fittipaldi as the Brazilian’s brakes began to fade but, against expectations, the ‘72 F1 champ put on a major charge during the closing laps to recapture second spot from Pearson. An intense battle between the two ended when Fittipaldi’s rear brakes locked up and he span.
Nevertheless, Fittipaldi still managed to take third behind winner Follmer and second placed Pearson.
Revson held off a late challenge from Foyt to claim fourth while Unser claimed sixth.
Allison faded to seventh with deflating rear tyres and Hulme, who felt his car was particularly weak, finished eighth.
Johncock and Petty had a coming together during the race’s early stages and both lost time following stops for repairs. They finished ninth and tenth respectively.
The race saw two non-finishers: McCluskey span into the Turn 9 wall on lap 14 and retired by which time Donohue had already parked up owing to a sticking throttle having not been able to get out of last place.
1973 Riverside Heat 3
Race three took place the following day (Sunday 28th).
Another reverse grid this time saw Donohue back on pole followed by McCluskey, Petty, Johncock, Hulme, Allison, Unser, Foyt, Revson, Fittipaldi, Pearson and Follmer.
Donohue took full advantage of his starting position and quickly established a lead over the chasing pack led by Hulme, Johncock and Petty.
Donohue and Hulme then proceeded to break clear while fourth-placed Petty went bouncing through the rough at the Esses on lap five. He rejoined just ahead of Fittipaldi who was last in a five-car group led by McCluskey. McCluskey was having best race so far until smoke began to pour from the back of his car and he was black flagged.
Soon afterwards, Johncock pulled into the pits from third with a jammed throttle linkage, a problem that then afflicted Petty who fell right to the back of the field.
The race took shape with Donohue firmly in control from Hulme who was well ahead of Unser and the rest who were in a tight group nose to tail.
Third placed Unser then began to close on the lead pair while Fittipaldi began to work his way through the field. By lap 22, Emmo had passed Pearson to take fourth which in turn became third when second placed Hulme ran out of brakes and span down to eighth. This left Unser chasing Donohue and Fittipaldi catching them both.
However, despite both Unser and Fittipaldi closing the gap in the final stages, they eventually ran out of laps and Donohue claimed his second win from three heats.
Pearson and Follmer were fourth and fifth respectively with Foyt and Revson right behind and Hulme catching them all in the final stages.
Allison was classified ninth after dropping back with a weakening engine which eventually expired.
McCluskey had of course been black-flagged with a smoking engine while Johncock and Petty also retired (both with sticking throttles).
Standings
Following Heat 3, Follmer and Unser were tied on 29 points, Donohue and Revson had 25 points apiece, Pearson was fifth with 24 and Foyt sixth on 22.
Failing to make the cut for the Daytona Finale were Fittipaldi (21), Hulme (18), Allison (12), Petty (12), Johncock (9) and McCluskey (8).
Post Riverside Upgrades
Between the last Riverside heat and the Daytona finale, seven of the cars were put up for sale (at $21,500 each) while the remaining eight were sent back to Germany for a few updates.
Stiffer dampers were installed, the brakes were adjusted to provide more rearward bias, a brace was added to help the drivers deal with the centrifugal forces expected from Daytona’s banking and an aluminium Gurney-style lip was fitted to the trailing edge of the rear spoiler.
By January the cars were on their way back across the Atlantic.
Upon arrival in Florida, Peter Gregg and Al Holbert had the job of shaking each car down in a weeks worth of testing at Daytona.
1974 Daytona Finale
The 25 lap IROC finale at Daytona took place on Thursday February 14th 1974 in the build up to that weekend’s NASCAR 500 mile season opener at the circuit.
The six drivers began practising in two pool cars on the Monday prior and were then given two flying laps to set their qualifying time.
Donohue took pole followed by Revson, Pearson, Follmer, Unser and Foyt.
The start of the race saw Follmer surge into an early lead while the chasing pack ducked and dived along the banking in hot pursuit before heading down to the infield.
Follmer clung on to his advantage as the group sprinted back towards the banking, but the lead pack was suddenly reduced to just four cars when Foyt’s engine let go and Pearson dropped back as he lost third gear.
By lap three, Donohue had slipstreamed ahead of Follmer to take first and the lead pair began to break free at around a second per lap. Third placed Revson was working hard to maintain his advantage of a few car lengths from Unser.
On lap nine, Follmer had a moment when he failed to find second gear which allowed Donohue to vanish into a comfortable lead.
Follmer continued to hold off the challenge from Revson and Unser until lap 13 when he crept into the pits having missed a gear which blew a valve in the engine.
Donohue subsequently eased his way to the chequered flag while Revson and Unser battled hard for second spot with Revson eventually claiming the runner’s up spot 100 yards from the line.
Pearson was classified fourth, two laps down after deliberately missing the infield twice.
Follmer and Foyt failed to finish.
Donohue picked up a cheque for $54,000 while Revson and Unser took home $21,000 and $19,000 respectively.
Unfortunately, the IROC series would never see such exotic machinery again and for the 1974-1975 contest Penske elected to use less espensive Chevrolet Camaros.
Text copyright: Supercar Nostalgia
Photo copyright: IROC & Porsche – https://www.porsche.com
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