About The IROC-Z CAMARO

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The Chevy Camaro IROC-Z was only around for a few years, but it is still an icon with traits unique to it alone!

The 1980s were not a great time for muscle cars as automakers had to deal with tighter emissions regulations and customer demands for better fuel economy. Most became gas-efficient daily drivers or high-performance cars meant for long-distance tracks. That included the long line of Chevrolet Camaros that had been a threat on every street across the nation in the earlier decades. In 1984 one such Camaro was designed and built for the '85 model year. The Chevrolet Camaro IROC-Z came out of the ashes to the adoration of Chevy fans. A unique style and look, with the highest performance 305 V-8 that the carmaker could get away with, and a style that was like no other. Let's jump in and discuss a few things that every car lover should know.

The International Race of Champions (IROC) began life in 1973 as the brainchild of David Lockton, developer of the Ontario Motor Speedway and organized by racing greats, Roger Penske, Les Richter and Mike Phelps. The IROC series was a North American auto racing competition that was promoted as an equivalent of an American motorsports All-Star Game. The competition consisted of four annual races that were initially ran on road courses, then primarily on American oval tracks, following stock car racing rules.

The IROC series called upon the best of the best of all the racing circuits to compete against each other. Drivers from varied racing disciplines; including Indy Car, Formula 1, SCCA, World of Outlaw and of course, NASCAR, which eventually contributed the majority of the drivers to the mix. Twelve racers were invited to compete, usually chosen from recent season championships in their respective series and major events, such as the Indy or Daytona 500.

The cars were identically prepared, evenly matched stock cars of the same make and model, set up by a single team of technicians (historically, NASCAR veterans Dick Trickle, Dave Marcis and Jim Sauter) in an all-out effort to derive a world champion based solely on driver ability. Beginning with the 1976 IROC season, a winner was determined by a total points-system in the four events. Throughout its three decade-long history, the nationally televised IROC races were widely acknowledged, as some of the most thrilling auto competitions ever run.

Kicking-off the series’ inaugural season, the first race of the 1974 campaign took place at Riverside International Raceway in Riverside, California, on October 27, 1973. The race was televised via tape delay on ABC, who provided coverage until 1980 and again from 1987-2003, splitting the other years with CBS (1984-86), ESPN and Speed Channel (2004-06). The first cars chosen for this automotive duel for supremacy, was the Porsche 911 Carrera RSR. Fifteen RSR’s were built and prepared by Robert Penske, all basically race-tuned versions of the street-going RS model.

The powerplant propelling the potent Porsches, was a race-ready version of the RS’ 3.0L flat-six with the famous “High Butterfly” injection system making 320hp. Wielded by a five-speed manual transmission, the 2100-lb. racecars combined RS and RSR components; including wide-panel bodywork, a fiberglass whale tail, Fuchs forged wheels, 4-piston aluminum brakes and a sparse all-race interior with plastic door handles to save weight.

After one season of racing Porsches, Penske realized that the cost to maintain them for racing was too expensive, and for IROC’s second season-1975, the decision was made to change from the pricey Porsches to a homegrown platform. With the absence of competing pony cars by 1975 leaving the segment wide open to General and Chevrolet, the 2nd-Gen Camaro was chosen as the great equalizer for auto racing’s best.

The first Camaros used from 1974-’76 were production-based, steel bodied cars, specially prepared by Penske Racing and IROC. Roger Penkse was no stranger to the Camaro, having found success with Chevrolet’s pony car in the 1968-’69 SCCA Trans-Am-Series. Initial power came from a Traco Engineering-built, 336ci Holley-carbureted Chevrolet small block making 440-horses and wielded by a T-10 Borg Warner 4-speed manual.

In 1977, Penske and IROC commissioned legendary NASCAR driver/builder Banjo Matthews to build new Camaros from the ground up. The new machines were complete tube frame racecars covered predominantly with fiberglass panels, powered by a re-worked, Traco-built 350-cid Chevy mill good for 450hp. The bodywork, T-10 4-speed gearbox, race suspension, Hurst-Airheart 4-wheel disc brakes and steering box came straight from GM’s parts bin. Fifteen IROC 2nd-Generation Camaros were built, racing the series until 1980. 

Unfortunately, when the economy took a nosedive, the races were suspended and after a four-year hiatus, 1984 would see IROC picking up where it had left off. Now co-sponsoring the series with Anheuser-Busch, Goodyear and True Value Hardware, Chevrolet offered-up the 3rd-generation Camaro Z28. This iteration of Chevrolet’s pony car would later become synonymous with the name, IROC.

The new racecar was built on a Banjo Matthews, IROC –fabricated, Grand National-style tube frame chassis like that of a full Winston Cup car. The combination of factory skins and fiberglass panels presented a hardcore mirror image of the streetcar. The powerplant propelling the 3rd-generation Camaro was a fresh set-up included a Katech Inc. race-prepped, forged aluminum 350 CID Chevrolet small block motor with 9:5.1 compression ratio making 470hp/400lb-ft in the 3350-lb. car. A 390cfm Holley carburetor, Hedman Hedders, a Richmond “Super T-10” 4-speed manual transmission, and stock car quick-change rearend with 3.50 gears for the oval track or 3.90s for road course.

The IROC series used the Chevrolet Camaro from 1975 to 1991, and because Chevrolet would race the Camaro under this sanctioning body, in 1985 Chevrolet entered into a licensing agreement with the racing series and as a result, obtained the right to use the IROC name on its production model Camaros. As a hat-tip to the race that spawned it, Chevrolet introduced the IROC-Z model of the Camaro. 

Until 1988 when Chevrolet dropped the production of the Z28, the IROC-Z was the most appealing and most recognizable model-option by almost all Camaro and general car enthusiasts alike. It was packaged as a Z28 option, and merely a check box on the order form that could be checked off if the consumer wanted to spend the extra $659.00 for the upgrade over the standard Z28, adding a number of chassis and handling improvements. The Camaro had some of the same designers as the Corvette, so it is safe to say that some of the components of the IROC-Z were from the 'Vette,” which is why the car could perform so well. 

Outside, it made its presence known with twin fog lamps inset in the grille opening (alongside the license plate mount), black headlight buckets and NACA simulated louvered hood inserts, uniquely styled decals, a more 'rounded' front fascia, as well as a very prominent and geometric chin spoiler with lower ground effects. It also received unique new 5-spoke 16”x8” aluminum wheels and shared the Corvette's Goodyear "Gatorback" unidirectional tires in 245/50/VR16 vs. the Corvette's 255/50/VR16.

The added unique front fascia and the upgraded suspension and sway bars made the car heavier by 52 pounds. This may not seem like a lot of weight, and in today's generation, it is not. Back when engines had already lost power, any added weight could make the difference between a 15-second quarter mile and a 14-second one. The Chevy Camaro IROC-Z was not one of the slowest cars on the road by any means but adding the performance package onto the car added weight that the vehicle could not have if the driver wanted to race down the strip.

The IROC-Z featured a lowered ride height, performance-calibrated front struts and springs, specially valved Delco-Bilstein shocks, larger diameter sway bars and a steering/frame brace known as the "wonder bar." Also available was an optional then-revolutionary fuel injection technology “Tuned Port Injection” (TPI) taken from the Chevrolet Corvette. Individually tuned runners channeled incoming air to each cylinder in the TPI V8, while computer-controlled port injectors delivered precisely metered fuel. If any of this sounds familiar, it is because the Corvette had similar features, which is why the IROC-Z was indeed a "Camaro that thinks it's a Corvette." 

Through the years, under the hood, the IROC-Z was available with several engine choices which included the base engine, an LG4 5.0-liter V8 with 155 horsepower and 245 lb.-ft- of torque, a carbureted L69 5.0-cubic inch V8 with 190 horsepower and 240 lb.-ft. of torque, and a 5.0 cubic-inch Tuned Port Injection LB9 available with 215 horsepower and 240 lb.-ft. of torque. In 1987, Chevrolet started making the 5.7 cubic-inch Tuned Port Injection L98 with output ranging from 225 to 240 horsepower, depending on the model year. The 5.0-liter engines were available with either a five-speed manual or four-speed automatic transmission whereas the 5.7-liter engine was only available with a four-speed automatic transmission.

The Chevrolet Camaro IROC-Z was built with one purpose in mind - to give drivers America's best-handling performance car. The IROC-Z was produced to compete on a track that was more about skill than raw power. The car could corner at high speeds without losing traction and get up to speed fast (0 to 60 in under seven seconds). Still, off-the-line speed was not what the '80s Camaros were designed for, especially the IROC-Z, which was strictly designed for performance.

The IROC-Z was a model that was far ahead of its time in every way and by the beginning of 1990 the last of the IROC-Zs were produced as Chevrolet's licensing/sponsorship agreement was about to expire. Chevrolet made the decision not to renew the agreement and b Because of this expiration and non-renewal, Chevrolet had to immediately stop production of the IROC-Z and reintroduce the Z28 as the performance model of the Camaro lineup. 

Chevrolet's decision was unfortunate because of the huge popularity of the IROC-Z, but in retrospect, it has now become a legend in the automotive world because the IROC-Z was only produced for just over 5 years. There were only 166,976 made during the years in production. If you subtract the ones that have been totaled in crashes and those that were stolen and parted out, not many remain. The IROC-Z is fast becoming the modern era's vehicle of choice among collectors. 

The idea behind a collectible car can have different meanings to people, but the one thing consistent across the board is that if a vehicle has low production numbers, the car will be more highly prized. That is simply because a collector will not want to buy a car for top dollar that every other person on their block can own. The rarer it is, the more collectors wish to own it, which is the only reason the IROC-Z is a prized collector's car. The IROC-Z was offered during the '80s, when consumers switched to more fuel-efficient vehicles that meet all the emissions regulations causing the production numbers were low due to a lack of sales, which is not as important as the fact that it is hard to find one that is restorable and drivable.

It is not fair to compare the '80s IROC-Z to the newer Camaros with the most innovative technologies of the decade. Keeping that in mind, one of the reasons that the IROC-Z was not a popular seller is that it was not one of the fastest Camaros that money could buy. Because of all '80s emissions regulations, the average quarter-mile times it could put up was only 15 seconds, while the Camaros of the previous decade could shoot down the same track in under 13 seconds. This may not be fair to say since the '80s version of every car was slower, but if speed was a priority, the '85 to '90 IROC-Z was not in contention.

The one great thing the Camaro IROC-Z had going for itself was its fuel economy, even with a more powerful motor than some other cars on the road. The average mpg of cars in the '80s was between 15 and 17 mpg in town, which the Chevrolet Camaro could match. Obviously, if the car was driven the way it was meant to be, the fuel mileage would go down a little. However, it was still a car that could be driven daily without draining the entire pocketbook.

Because of the time period, the engines could not put out the power and torque gearheads expected from a Camaro. The base model came with a 305 engine that only put out around 215 horsepower and 275 pound-feet of torque. The biggest engine that the car received was the 350 that was used in the Corvette, which could produce 225 horsepower and 330 pound-feet of torque. Just to give a comparison, let's look at a 1969 Chevrolet Camaro RS ZL-1. It could produce over 500 horses and could pound out 450 pound-feet of torque. Quite a difference, especially when thinking that a newer model should have better numbers.

Information researched and provided by GM Authority, Top Speed and  Wikipedia