- 1985 to 1990 Camaro IROC-Z Spotter's Guide - 

Many thanks go to Jim Irace and Willie (Thirdgen.org History Moderator) for their help and contribution to this article.   We've been wanting to do this for some time now, just never really got around to it.  Well, seeming we've been getting approached more and more with questions pertaining to buying a used IROC and whether it's "authentic" or not, we decided to write this article.   Throughout the IROC-Z era, the basic look of the car looks the same.  We'll point out some things that differ with each model year IROC-Z along with what to look for with different options (i.e. 305 Throttle Body Injection versus 350 Tuned Port Injection).

What makes an IROC and IROC?  Well, after looking around for one, and seeing enough of them, you should be able to point out what is actually an IROC and what is not.  We won't kid you here.  There are several "IROC" wannabe's out there - ones who make a third generation camaro "look" and even drive like an "authentic" IROC-Z.  Some people do a really good job, some people do not.  The best way to tell if the car is an "authentic" IROC-Z is to look at the VIN number and, most importantly, the RPO codes (granted the "faker" didn't swap out the center console with a real IROC-Z, then you would have to decode all of the numbers and figure out if the vehicle is indeed an IROC.)  Just like the Z-28's, all IROC-Zs came with black painted headlight inserts.  But not like Z-28's, the IROC-Z's ground effects were the same color as the body, versus the two tone paint schemes of the Z-28.

The VIN number is located on the dash, drivers side, in plain view from the outside of the windshield.  Decoding the VIN will tell the basics of the car and the engine it is equipped with.  Not much to really tell, unless the VIN states the car was a V6 and the seller says it's an IROC.  The IROC-Z always came with a V8.  

The RPO codes are located on a sticker, usually located in the center console/passenger side wall.  The RPO code to look for in a 1985 to 1987 IROC-Z is B4Z.  The RPO code to look for in a 1988 to 1990 IROC-Z is Z28 (since the IROC-Z "replaced" the Z-28 from 1988 to 1990, GM elected to use the Z28 RPO code for that option from 1988 to 1990).    As a little tidbit, the Z-28 resumed production AS a Z-28 for the 1991 model year as GM's licensing for IROC ended December 31st, 1989.  The limited number of 1990 IROC-Z's is accounted for the number of cars produced, under the IROC license, until December 31, 1989 for the 1990 model year.

For Starters:  To narrow down what model year "sub era" of IROC-Z you are looking at, play close attention to the IROC-Z logo on the door.  From 1985 to 1987, the logo was towards the front of each door, whereas from 1988 to 1990 (if the car does not have the 'sticker delete' option), they were towards the rear of each door.  Note the striping layout between each 'sub era.'   From 1985 to 1987, the stripes were arranged where the black stripe was on the bottom of the two (silver on top as noted in the photo below).  From 1988 to 1990, this black stripe was on the top of the two (again, if the car does not have the 'sticker delete' option.) Also note the wheel styles. A all 1985 to 1987 IROC-Zs had the 16" aluminum wheels with the single (wider) line through each spoke as standard.  From 1988 to 1990, the 16" aluminum wheel was now an option, however, all later style IROC-Z wheels had two (thinner lines) through each spoke whether it was 15" or 16" (except for 1988 15" standard wheel - we'll cover this later).
Shot of the stripe layout of the 1985 to 1987 model year IROC-Zs as well as the wheel style.  Also note that the IROC-Z logo on the door is towards the front.  The 16" aluminum wheels (shown) were the only style available for the IROC-Z package for the 1985 to 1987 model years.	Shot of stripe layout of the 1988 to 1990 model year IROC-Zs as well as the wheel style.  Also note that, on car shown, the IROC-Z logo on the door is towards the rear.  The 15" aluminum wheels (shown) were the base wheel option on the IROC-Z for the 1989 and 1990 model years.

- 1985 Model Year -

The IROC (International Race Of Champions) began using the Camaro as the official vehicle.  To commemorate this, Chevy made an IROC model for the Camaro.  The IROC-Z was option B4Z on the option sheet and could only be ordered with the Z28 option package.  The ride height was lower than a standard Z-28, and featured performance-calibrated front struts and springs, Bilstein rear shocks and 16 inch aluminum wheels with Goodyear Eagle 245/50/16 tires.  

This new performance icon boasted skidpad numbers within the range of .90 g.  The top offering under the hood was the brand new TPI 305 (LB9) which boasted 215 horsepower and 275 ft/lbs of torque.  Recipients of this engine wore the badge.  This was the most powerful 305 automatic ever offered in the IROC.  The 190 horsepower HO 4bbl 305 and the standard output 155 horse LG4 were the other available motors.

The IROC also came with a redesigned front fascia with a more rounded appearance and a deeper chin spoiler with lower ground effects.  The new fake hood louvers were introduced on the Z28 and IROC.  The IROC was available in Yellow, Bright Blue Metallic, Black, Silver Metallic and Red.

		A 'unique' feature of the 1985 IROC-Z, is that there is no third brake light.  Neither near the top of the hatch window, nor in the rear spoiler.
		Colors available were White, Black, Bright Red, Yellow Gold, Bright Blue and Silver.  1985 was the only model year you could get a Silver IROC-Z.
		All 1985 IROC-Zs have the 85MPH speedometer, regardless of engine or transmission option.
		Automatic transmission equipped IROC-Zs have the round gear selector handle for 1985.  All LB9 optioned IROC-Zs required automatic transmission.
		The 5000 RPM redline tachometer was used on LG4/L69 (305 CID "Quadrajet" Carbureted) equipped 1985 IROC-Zs, regardless of transmission.
		The 5500 RPM redline tachometer was used on LB9 (305 Tuned Port Injection) equipped 1985 IROC-Zs, regardless of transmission.
		16" aluminum wheels with the single (wider) line through each spoke as standard on all 1985 IROC-Zs.
Base Wheel 16" Aluminum	Upgrade Wheel None

- 1986 Model Year -

In 1986, the IROC received slightly different engine packages.  The 86 IROC is the armpit of the entire run.  The 305 block in 1986 now had a one piece rear main seal.  The TPI 305 was the lucky recipient of the LG4 camshaft, and the result was a drop of 25 horses and almost a half second longer run to 60mph.  Chevrolet did allow 50 IROCs out the door with the 220HP L98 350 TPI, but word has it, it wasn't for production release.  Beware when somebody sells an 86 IROC-Z with a stock 350 TPI engine.  CHECK THE VIN for accuracy.

Chevy also let an undisclosed number of these cars out with the T5 (5-speed transmission) as part of the 1LE racing option that also included air conditioning delete, radio delete, as well as the deletion of all power accessories.  The 1LE option was not available with T-tops, but did come with specially calibrated springs, shocks and sway bars.

Visually, not too much changed on the 86 IROC.  The government mandated 3rd brake light found its way to the top of the rear hatch near the roof line.  Curiously, rear window louvers became a factory option this year.  Some of the 86 IROCS came with the new 140mph speedometer.  86 was also the first year for the base coat/clear coat paint system as standard equipment.

		A 'unique' feature of the 1986 IROC-Z, is that the third brake light was located on top of the hatch window, close to the roof.  Later year, base model Camaros had the brake light in the same location as most did not have a rear spoiler.
		Colors available were White, Black, Bright Red, Yellow Gold, Bright Blue and Dark Red Metallic
		Most 1986 IROC-Zs have the 85MPH speedometer, regardless of engine option.  Later on in production, the 145MPH speedometer was introduced on TPI equipped IROC-Zs, regardless of transmission.
		Towards the end of the 1986 model year production line, the 145MPH speedometer was used on TPI equipped IROC-Z, regardless of transmission.
		Automatic transmission equipped IROC-Zs had the round gear selector handle for 1986.  All LB9 optioned IROC-Zs required automatic transmission.
		The 5000 RPM redline tachometer was used on all production IROC-Zs for the 1986 model year, regardless of transmission.
		16" aluminum wheels with the single (wider) line through each spoke as standard on all 1986 IROC-Zs.
Base Wheel 16" Aluminum	Upgrade Wheel None

- 1987 Model Year -

1987 brought about only minor changes to the IROC.  The motors now had the new center bolt style heads and the intake manifolds had a revised bolt hole angle to accommodate the different heads.  The motors also made the switch to hydraulic roller camshafts.  This gave a 3.5% increase in gas mileage, and an extra 5 horsepower.  The TPI 350 was now widely available, but only with the 700R4 automatic.  Recipents of this engine wore the badge and the 305 TPI recipients wore the conventional badge.

Visually, the 87 is identical to the 86 model, except that the third brake light moved from up on the rear hatch, to down in the rear spoiler.

		On the 1987 IROC-Z, the third brake light was on the spoiler of the rear hatch lid.  Base Camaro models still used the upper hatch location (towards to roof) for the location as most did not have a rear spoiler.
		Colors available were White, Black, Bright Red, Yellow Gold, Bright Blue and Dark Red Metallic
		The 85MPH speedometer was the equipment used on the 305 CID (5.0L) "Quadrajet" carbureted engine (LG4) equipped IROC-Z, regardless of transmission.
		The 145MPH speedometer was used on the 305 CID (5.0L) Tuned Port Injection engine (LB9) and the newly available 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Z, regardless of transmission and includes convertibles with the LB9 option.
		1987 was the first year you could get the T5 5-speed manual transmission behind the LB9, 305 TPI engine.
		Automatic transmission equipped IROC-Zs had the square-shaped gear selector handle for 1987.
		The 5000 RPM redline tachometer was used on all 305 CID (5.0L) "Quadrajet" carbureted engine (LG4) equipped IROC-Zs, regardless of transmission.  The 5000 RPM tachometer was also used on 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with automatic transimissions
		The 5500 RPM redline tachometer was used on all 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with manual tranmissions, as well as all 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Zs.
		16" aluminum wheels with the single (wider) line through each spoke as standard on all 1986 IROC-Zs.
Base Wheel 16" Aluminum	Upgrade Wheel None

- 1988 Model Year -

1988 brought about some welcome changes in the horsepower department, as well as a somewhat revised exterior scheme.  The Z28  was discontinued, and the IROC was now its own model utilizing the Z28 RPO code (instead of the B4Z code).  For the first time in the history of the camaro, no carburated camaros were available.  All motors offered fuel injection of some sort.  The base IROC motor had the TBI injection that was very similar to what was found on the trucks.  A new camshaft finally found its way into the 305 TPI and boosted horsepower to 195 HP in the automatic version, and a stout 220 HP when backed with the T5, 5-speed manual transmission.  The 350 TPI also got a small horsepower boost to 230 HP.  All of the V8s, starting in 88, had "guided rocker arms" that featured a stamped-in lip on each side of the pad that contacts the valve stem.

The exterior of the IROCs received a mild update for 1988.  The most noticable difference is that the wheels have been slightly changed.  Instead of one line through the center of each spoke, there were now two lines (on the, now, optionally equipped 16" aluminum wheel), and the center area was a little different.  Here's an interesting tidbit: for the first time, the 16" wheel was an option on the IROC.  The car came standard with a 15" version.  Along with that, the IROC-Z decal moved to the rear of the door instead of the front.  The stripe along the ground effects line now had the black line on top of the other.  The silver Z-28 badges on the exterior have been replaced with orange IROC-Z logos.

		On the 1988 IROC-Z, the third brake light was on the spoiler of the rear hatch lid.  Base model Camaros were the Sport Coupe model, consisting of either a pedistal mount spoiler (exclusive to 1988 we believe), or the three piece spoiler; either one consisting of the brake light in the spoiler itself as well.   The base model Camaros received silver or grey ground effects and can be considered the "preliminary" RS as in 1989, the RS was the base Camaro and wore body colored ground effects versus silver or grey.
		Colors available were White, Black, Bright Red, Gunmetal Gray, Medium Orange (3,010 made) and Dark Red Metallic.  1988 was the only model year you could get an IROC-Z in Gunmetal Gray and Medium Orange.
		The 115MPH speedometer was the equipment now used on base equipped IROC-Zs for 1988.  This would be the 305 CID (5.0L) Throttle Body Injection (TBI) LO3 equipped IROC-Z, regardless of transmission. The 305 CID (5.0L) Tuned Port Injection (TPI) LB9 equipped IROC-Z with the automatic transmission also recieved the 115MPH speedometer.
		The 145MPH speedometer was used on the 305 CID (5.0L) Tuned Port Injection engine (LB9) with the 5-speed transmission and the 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Z and includes convertibles with the LB9 option.
		Automatic transmission equipped IROC-Zs had the square-shaped gear selector handle for 1988.
		The 5000 RPM redline tachometer was used on all 305 CID (5.0L) TBI engine (LO3) equipped IROC-Zs, regardless of transmission.  The 5000 RPM tachometer was also used on 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with automatic transimissions
		The 5500 RPM redline tachometer was used on all 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with manual tranmissions, as well as all 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Zs.
		15" aluminum wheels were now the standard on all IROC-Zs starting in 1988.  This particular style was only used for the 1988 model year only, replaced in 1989 with a style, similar to the newly designed 16" aluminum upgrade wheel.
Base Wheel 15" Aluminum	Upgrade Wheel 16" Aluminum

- 1989 Model Year -

1989 brought about some nice horsepower increases.  The TPI 305 5-speed jumped to 230 HP if the dual catalytic converters were ordered (part of G92 package), and with the dual cats, the L98 350 TPI jumped to 240 HP, with a staggering 345 ft/lbs of torque!  The TPI systems changed slightly.  For the first time, the 9th cold start injector was no longer used.

Visually, nothing changed from the 1988 model, except for one key item - starting in 1989, the rear seat belts were shoulder harness, whereas the 1988 and prior year Camaros used the rear lap belt.  

		On the 1989 IROC-Z, the third brake light was on the spoiler of the rear hatch lid.  Base model Camaros were now the RS model, basically the same car as the 1988 Sport Coupe, just bore the RS name, consisting of the three piece spoiler, in which the brake light would be located in the spoiler itself as well.
		Colors available were White, Black, Bright Red, Bright Blue and Dark Red Metallic
		The 115MPH speedometer was the equipment used on base equipped IROC-Zs and convertible models for 1989.  This would be the 305 CID (5.0L) Throttle Body Injection (TBI) LO3 equipped IROC-Z, regardless of transmission and the convertibles received the 115MPH speedometer, regardless of engine.
		The 145MPH speedometer was used on the 305 CID (5.0L) Tuned Port Injection engine (LB9) and the 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Z, except for the convertible model, which used the 115MPH, regardless of engine (LB9 or L98)
		Automatic transmission equipped IROC-Zs had the square-shaped gear selector handle for 1989.
		The 5000 RPM redline tachometer was used on all 305 CID (5.0L) TBI engine (LO3) equipped IROC-Zs, regardless of transmission.  The 5000 RPM tachometer was also used on 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with automatic transimissions
		The 5500 RPM redline tachometer was used on all 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with manual tranmissions, as well as all 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Zs.
		15" aluminum wheels were the standard on all IROC-Zs in 1989.  The newly designed 15" wheel looks very similar to the 16" aluminum upgrade wheel option, just slightly smaller.  To tell the difference, look at the tire size on the tire itself.  For example, in 245/50/ZR16, the R16 notes that it is a 16" wheel and an R15 would signify a 15" wheel.
Base Wheel 15" Aluminum	Upgrade Wheel 16" Aluminum

- 1990 Model Year -

The IROC-Z Camaro ends in a bang.  This is the first year the 1LE high performance option became widely known.  The 1LE featured 4 wheel disk brakes, a 3.42 posi rear end, an aluminum drive shaft, large 12" front rotors, aluminum calipers, engine oil cooler, larger anti-roll bars and gas tank baffles.  There were also numerous spring rates available.  The package could only be ordered without air conditioning or fog lamps.   1990 also marked the year the the TPI systems changed from the Mass airflow system to the speed density system.  The speed density system allowed an extra 5 horsepower for the 350, upping the ante to 245 HP.  The LO3 305 TBI dropped as the base model engine.  The only engines you could get in your 1990 IROC was either the 305 TPI (w/ or without the G92 package) or the 350 TPI.  Also, for the 1990 model year, the removable roof panels (T-Tops) were not offered in the 1990 IROC-Z equipped with the 350 TPI engine option.

Visually, the exterior of the 1990 IROCs did not change, but looking through the windows will show that they now had a driver side air bag as well as revised instrument cluster. 

1990 marked the last production model year for the IROC-Z, ending production as GM's licensing for IROC ended December 31st, 1989.  The limited number of 1990 IROC-Z's is accounted for the number of cars produced, under the IROC license, until December 31, 1989 for the 1990 model year.

		On the 1990 IROC-Z, the third brake light was on the spoiler of the rear hatch lid.  Base model Camaros were the RS model, consisting of the three piece spoiler, in which the brake light would be located in the spoiler itself as well.
		Colors available were White, Black, Bright Red, Bright Blue and Dark Red Metallic
		The 115MPH speedometer was on convertible models only, regardless of engine.
		The 145MPH speedometer was used on the 305 CID (5.0L) Tuned Port Injection engine (LB9) and the  350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Z, except for the convertible model, which used the 115MPH speedometer, regardless of engine.
		Only in 1990, was the dash "IROC-Z" logo yellow.
		Automatic transmission equipped IROC-Zs had the square-shaped gear selector handle for 1990.
		The 5000 RPM redline tachometer was used on the 305 CID (5.0L) TPI engine (LB9) equipped IROC-Zs, without the G92 performance package.
		The 5500 RPM redline tachometer was used on all 305 CID (5.0L) Tuned Port Injection engine (LB9) equipped IROC-Zs with the G92 performance package, as well as all 350 CID (5.7L) Tuned Port Injection engine (L98) equipped IROC-Zs.
		15" aluminum wheels were the standard on all IROC-Zs in 1990.  The 15" wheel looks very similar to the 16" aluminum upgrade wheel option, just slightly smaller.  To tell the difference, look at the tire size on the tire itself.  For example, in 245/50/ZR16, the R16 notes that it is a 16" wheel and an R15 would signify a 15" wheel.
Base Wheel 15" Aluminum	Upgrade Wheel 16" Aluminum

- Engines -

Engine	Year Available / Standard or Optional Equipment
LG4 4bbl Carbureted 305	1985 - Standard 1986 - Standard 1987 - Standard
L69 4bbl Carbureted 305 High Output	1985 - Optional 1986 - Optional
LB9 Tuned Port Injection 305	1985 - Optional 1986 - Optional 1987 - Optional 1988 - Optional 1989 - Optional 1990 - Standard engine (G92 performance package is optional)
LO3 Throttle Body Injection 305	1988 - Standard 1989 - Standard
L98 Tuned Port Injection 350	1987 - Optional (w/ AT only) 1988 - Optional (w/ AT only) 1989 - Optional (w/ AT only) 1990 - Optional (w/ AT only)

MT = Manual Transmission (5-Speed T5), AT = Automatic Transmission (700R4)

- Transmissions -

- Wheels -

Wheel Style	Year Available / Standard or Optional Equipment
16" Aluminum	1985 - Standard 1986 - Standard 1987 - Standard
15" Aluminum	1988 - Standard
15" Aluminum	1989 - Standard 1990 - Standard
16" Aluminum	1988 - Optional 1989 - Optional 1990 - Optional

- Colors -

Exterior Color	Year Available
White	1985 1986 1987 1988 1989 1990
Bright Red	1985 1986 1987 1988 1989 1990
Black	1985 1986 1987 1988 1989 1990
Yellow Gold	1985 1986 1987
Bright Blue	1985 1986 1987 1989 1990
Dark Red (Flame Red)	1986 1987 1988 1989 1990
Silver	1985
Medium Orange	1988
Gunmetal Gray	1988

- Striping and Decals -

Style/Location	Year / Option (if applicable)
IROC-Z logo towards front of each door.  Black stripe on bottom of two.	1985 - Standard (All) 1986 - Standard (All) 1987 - Standard (All)
IROC-Z logo towards rear of each door.  Black stripe on top of two.	1988 - Standard (DX3 Sticker Delete Optional) 1989 - Standard (DX3 Sticker Delete Optional) 1990 - Standard (DX3 Sticker Delete Optional)

- Speedometers -

Speedometer	Year Available / With What Equipment
85MPH	1985 - All 1986 - All (exc. later 86 models with 305 TPI) 1987 - LG4 (305 4bbl Carb)
115MPH	1988 - LO3 (305 TBI) 1989 - LO3 (305 TBI) and all convertibles, regardless of engine
145MPH	1986 - Later models with 305 TPI 1987 - LB9 (305 TPI) and L98 (350 TPI), including convertibles w/ LB9 1988 - LB9 (305 TPI) and L98 (350 TPI), including convertibles w/ LB9 1989 - LB9 (305 TPI) and L98 (350 TPI), excluding convertibles
115MPH (Newer Style)	1990 - All convertibles, regardless of engine
145MPH (Newer Style)	1990 - LB9 (305 TPI) and L98 (350 TPI), excluding convertibles

- Tachometer -

Redline	Year Available / With What Equipment
5000 RPM (4500 RPM Yellow)	1985 - LG4 (305 4bbl Carb), L69 (305 4bbl H.O. Carb) 1986 - All 1987 - LG4 (305 4bbl Carb), LB9 (305 TPI) w/ Auto 1988 - LO3 (305 TBI), LB9 (305 TPI) w/ Auto 1989 - LO3 (305 TBI), LB9 (305 TPI) w/ Auto
5500 RPM (5000 RPM Yellow)	1985 - LB9 (305 TPI) 1986 - None 1987 - LB9 (305 TPI) w/ 5-Speed, L98 (350 TPI) 1988 - LB9 (305 TPI) w/ 5-Speed, L98 (350 TPI) 1989 - LB9 (305 TPI) w/ 5-Speed, L98 (350 TPI)
5000 RPM (Newer Style) (4500 RPM Yellow)	1990 - LB9 (305 TPI) w/o G92 Perf Pkg
5500 RPM (Newer Style) (5000 RPM Yellow)	1990 - LB9 (305 TPI) w/ G92 Perf Pkg, L98 (350 TPI)

- Third Brake Light Placement -

Location	Year
No Third Brake Light	1985
Top of Hatch Window near roofline	1986
Bottom of Hatch Window in Rear Spoiler	1987 1988 1989 1990

- Allan Reinike with contributions from Jim Irace and Willie

If you would like to contribute your articles to IROCZone.com, e-mail us at info@iroczone.com!