Fast Lane Flashback
The 1985 - 1990 Chevrolet Camaro Iroc-Z
By: Lawren Dame \ Associate Editor \ May, 28 2014
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The Chevrolet Camaro came roaring to life in 1967 in an effort to compete with the Ford Mustang. By the late 1970s, there was quite a bit of debate over how the next Camaro should appear. Though many pushed for it to move on to front-drive setup, the Camaro’s chief engineer determined that the third generation Camaro’s first priority was handling, and therefore it necessitated rear drive. While retaining rear drive, the Camaro also kept its traditional live rear axle, while replacing the old leaf springs with coils and double control arms with a pair of struts and springs. The car’s unibody was optimized as well, resulting in handling described as the best available during its time
By 1985, the revolutionized Camaro had a new name and an even newer design—now the Camaro IROC-Z. This new car was named after the International Race of Champions, a race car series sponsored by Chevrolet from the start of IROC-Z’s production, up to 1990, when Dodge took over sponsoring the series.
The 1985-1990 IROC-Z was originally option B4Z on the option sheet and appeared only as a performance and appearance package on the Z28 until it became its own trim level in 1988. The Camaro IROC-Z was truly the most iconic Camaro of the 80s. It was designed to ride fast with Tuned Port fuel injection (TPI), a lowered ride height complete with unique front struts, Delco-Bilstein rear shocks, and chassis reinforcements. In addition, the Camaro’s interior was pure muscle, including sport gauges and a speedometer with double needles depicting mph on one side, and kph in orange on the other. The muscle look carried over to the body kit complete with rocker panels with IROC-Z decals.
The IROC-Z made several developments through the years before eventually rolling to a stop in 1990. With each year of its production, the muscle car underwent several changes, including option choices, modifications to its brake lights, model color, gears, and wheels. To take a closer look at these changes, we’ll examine the Camaro year by year through its lifetime as the IROC-Z.
To start, as aforementioned, the IROC-Z’s birth brought forth several new changes to the Chevrolet Camaro. For example, like the other Z28s, every IROC-Z came with black painted headlight inserts; however, its ground effects were the same color as the body, whereas the Z28’s paint scheme were two-toned.
Other key defining elements of the first IROC-Z models were a lower ride height than the Z28, showcasing Bilstein rear shocks, 16-inch aluminum wheels wrapped in Goodyear Eagle 245/50/16 tires, performance-calibrated front struts and springs, and skidpad numbers ranging within .90g. Out of everything offered under the hood, the Tuned Port Injection 305 (LB9) was by far the greatest feature, with 215 horsepower and 275 ft/lbs of torque, making the IROC-Z the most powerful automatic trans equipped IROC ever offered.
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One characteristic unique to the 1985 IROC-Z is that it didn’t contain third brake lights anywhere on the car. Colors included silver, gold yellow, white, black, bright red, and bright blue. Door emblems, labeled “IROC-Z,” were located below the sideview mirrors, toward the front of the door. The IROC also had a redesigned front fascia; it contained a deeper chin spoiler and was more rounded out in appearance. Every 1985 IROC-Z had an 85 mph speedometer as well. All of the LB9 IROC-Zs required automatic transmission, and this meant they were rigged with a round gear selector handle. Each IROC which was equipped with LB9 (305 Tuned Port Injection) contained a 5500 RPM redline tachometer. Lastly, each 1985 IROC-Z had 16-inch aluminum wheels with a single wide line trailing through each wheel’s spoke.
The 1986 Camaro IROC-Z was visually very similar to the 1985 model. A few changes were made; for example, the standard basecoat/clear coat paint system was first implemented in this year. The IROC-Z also gained the third brake lights at the top of the rear hatch window, now required by law, as well as the option for rear window louvers in an effort to block out sun and defend against overheating the cabin. Some 1986 IROCs also came with the new 140 mph speedometer. This was the peak production year for the IROC-Z, with a total of 49,585 produced.
The option code remained the same as that of the previous 1985 model—B4Z—but the engines were tweaked a bit. In 1986, Chevrolet changed their rear main seal design, so that the 305 block’s two piece rear main seal was now exchanged for a one piece. Models containing the TPI 305 received the LG4 camshaft, which dropped horsepower by 25 from 215 to 190. This also caused the Camaro to take a nearly half second longer run to 60 mph. Rumor has it that 50 IROC-Zs got away with a 220 horsepower L98 350 TPI not meant for production release. The colors offered for the 1986 IROC included bright red, dark red metallic, bright blue, yellow gold, white, and black, with the most popular being the bright red. The majority of IROCs were equipped with 85 mph speedometers, but the 145mph speedometer was introduced later on in the year for those with TPI engines. The LB9 fitted IROCs required the automatic transmission, again with a round gear selector. All IROCs produced for the year included the 5000 RPM redline tach, and these IROCs maintained the same 16 inch aluminum wheels as the previous year.
1987 was yet another year with minimal changes made to the beloved IROC-Z. There was a dip in production compared to the previous year, as a total of 38,889 total IROCs were produced for the 1987 model. When simply viewing outward appearance, the 1987 IROC appears nearly identical to 1986, aside from the movement of the third brake light from the rear hatch to further down on the rear spoiler. However, base Camaro models did not have real spoilers and thus retained the original location. The same body colors were offered this year, but leather was now offered as an option for the interior.
Visual appearance aside, the 1987 IROC-Z saw a few changes from within. Motors for these IROCs were now supplied with center bolt style heads, and intake manifolds were brushed up with a new bolt hole angle to fit with the new heads. Additionally, the motors switched over to hydraulic roller camshafts, which increased horsepower by 5 and the gas mileage by 3.5%. This was also the year that the ignition system was replaced with the new High Energy Ignition (HEI) System.
This was the first time since 1969 that the convertible option was made available, as well as the first year that the T5 5-speed manual transmission was available behind the LB9 305 TPI engine. The 220hp 5.7 Liter 350ci engine was not available for the convertible, nor was it visually distinct from the 5.0, though its recipients wore a “5.7 Tuned Port Injection” badge as opposed to the 305 TPI’s simple “Tuned Port Injection” badge for clarification. To further distinguish the two, all 5.7 Camaros came with a square shifter knob whereas every other IROC had round ones. Each 5.7 also had an automatic transmission and rear disk brakes, and came with a tachometer that was yellow at 5000 and red at 5500.
With a total of 27,811 Camaros produced for the year, 1988 was the year that the exterior of the Camaro IROC-Z received a mini revolution. Most notably, the IROC received the new standard option for 15-inch aluminum wheels as opposed to the previous years’ 16-inch ones. Double lines now raced through the center of each spoke, and the spokes met the center of the wheel in a slightly different design. The “IROC-Z” decal also took a step backward, moving from the front of the door to the rear. Available colors for this year were gunmetal gray, white, black, bright red, dark red metallic, and the new medium orange, with 3,010 produced. Interestingly, 1988 was the only year with the option of gunmetal gray or medium orange. Also in 1988, the Z28 model was discontinued and officially replaced with the IROC-Z, now using the Z28 RPO code instead of the B4Z. For this reason, the silver Z28 exterior badges were swapped with orange IROC-Z ones.
A major change came to the Camaro’s motor, as well: suddenly, for the first time ever, the carbureted Camaro was laid to rest. Now, all motors were instead equipped with some form of fuel injection. The 305 TPI was now fitted with a new camshaft which intensified the horsepower of Camaros equipped with automatic transmission to 195, and those with T5 5-speed manual transmission were raised to 220 horsepower. With the extra power boost, IROCs with the 350 TPI could now zoom away with 230 horsepower. Also starting in 1988, all V8 engines were furnished with guided rocker arms.
Two different speedometers and tachometers were used in 1988. Recipients of the 115 mph speedometer and 5000 rpm redline tachometer were included on the 305 CID (5.0L) Throttle Body Injection (TBI) LO3 equipped IROC-Z, regardless of transmission, and the 305 CID (5.0L) Tuned Port Injection (TPI) LB9 equipped IROC-Z with automatic transmission. Lucky recipients of the 145 mph speedometer and 5500 rpm redline tachometer were those with the 305 CID (5.0L) Tuned Port Injection engine (LB9) with the 5-speed manual transmission, as well as those with the 350 CID (5.7L) Tuned Port Injection engine (L98).
1988 brought a few horsepower increases to the IROC-Z, then 1989 blew these clear away. With the option of dual catalytic converters making the IROC a true dual car, the TPI 305 leaped up to 230 horsepower, and the L98 350 TPI took it a step up to 240 horsepower, gaining 345 ft/lbs of torque. The Tuned Port Injection system was changed as well, with the discontinuation of the 9th cold start injector. A total of 24,007 Camaros were produced in this second-to-last year of the IROC-Z’s production.
From a visual point of view, this model was virtually the same as the previous year—the color scheme offered was back to white, black, bright red, dark red metallic, and bright blue. One change was made, however; the backseats were equipped with shoulder harness seatbelts, as opposed to the previous years’ rear lap belts. The standard 15-inch aluminum wheels also received a slight makeover, so that it now looked identical to the 16-inch version, aside from the size difference.
The Camaro IROC-Z’s final year of production finished off with a total production of 5,517. Though not the highest production it had ever seen, it still underwent many notable changes for the year. 1990 was the first year that the 1LE high performance option sprung to life, featuring 4 wheel disk brakes, an aluminum drive shaft, 12-inch front rotors, engine oil cooler, larger anti-roll bars, gas tank baffles, aluminum calipers, and a 3.42 posi rear end. This package was only available without air conditioning or fog lamps.
This year, the TPI systems took a transformation from the mass airflow system to the speed density system, pushing the TPI 350’s horsepower higher than ever, to a horsepower of 245. Conversely, the LO3 305 TBI fell off the map and lost its spot as base model engine, so that the available engines for this IROC-Z were only the 305 TPI or the 350 TPI. Camaros with 350 TPI engines were unable to offer removable roof panels (T-Tops), however. Regarding speedometers, in 1990 the 115 mph speedometer was reserved exclusively for convertible models, and the 145 speedometer on just the IROCs with the 305 CID (5.0L) Tuned Port Injection engine (LB9) or the 350 CID (5.7L) Tuned Port Injection engine (L98).
Once again, the external visual aspects of this Camaro remained the same, but the inside of this muscle car contained a few new changes: an airbag on the driver’s side, and a revised instrument cluster. The same body colors were offered, but there was one color change unrelated to the paint: 1990 was the first and only year in which the “IROC-Z” logo was displayed in yellow on this f-body.
GM’s licensing for the IROC ended as of December 31, 1989, bringing its production to a swift close. Nonetheless, the Camaro IROC-Z lives on in infamy as one of the most iconic muscle cars Chevrolet ever produced.