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Difference Between IROC-Z and Z28

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Old Jun 28, 2005 | 11:57 AM
  #1  
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From: Holland, Pa
Car: 1986 Chevy Camaro IROC-Z
Engine: LG4 5.0 305 4 Barrel
Transmission: T-5 5 speed
Difference Between IROC-Z and Z28

I bet alot of people have posted about this, but the search feature on this site really doesn't do much for giving me an answer so might as well ask it again. What is the different between the Z28 and IROC-Z. I know for a fact that the RS is like the base model (besides the older sport coups) and has the apperance package. And the IROC-Z looks like it has the best of both apperance and performance. Now does the Z28 just have the performace package and not really as much apperance package like the IROC-Z has? I am looking at this 86 Z28 and I just want it to have as much as the factory performance as like the IROC-Z had. Did the Z28 have most of the same Factory performace options? This Z28 looks to have the smaller 15" rims and I really don't know if it has rear disc brakes. Besides maybe not having that should it have all the same handing and suspension like the IROC-Z? Can anyone clear this up? I already know most of the major differences between the 3 camaro's, but the smaller things need some help.
Old Jun 29, 2005 | 04:11 PM
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From: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
I may be wrong, BUT,
The IROC got the 16" rims 85-87 the Z28 got 15" rims
The IROC got special badges than the Z28 I beleve.
The IROC had a slightly better suspension. Wonderbar is one specific upgrade. not sure about the other suspension pieces like the sway bars. A Wonderbar can be had for $50 from TDS, a must have.

Performance wise, I think the engines were the same, IE, a 305TPI was the same for either one, so was the HO and the LG4.

If you want performance, 86 seems to be a lonley year. The 86 TPI was the doggiest due to new regulations, however this can be easily changed by a cam and a little PROM tuning. The HO(L69) and the LG4 in 86 were unchanged for 86.

John
Old Jun 29, 2005 | 09:22 PM
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From: Where the heck am I !..Oh yeah,in Lousy-ana.
Car: 1991 Z28
Engine: 350 TPI
Transmission: 4L60 automatic
Early production 1991 Z28s got the wonderbars also(probably just the 350tpi cars).Most say it was just a parts bin leftover and some people were just lucky to get them.
So why didn't GM just sell the extra wonderbars at their dealerships instead of putting them on the early '91Z28s.Mine has one btw.
Old Jun 29, 2005 | 09:34 PM
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also the steering boxes are different from the IROCS and the Z28's
Old Jun 29, 2005 | 10:42 PM
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In 87 the the 350 made it's return, but was only available in the IROC-Z. The top engine in the Z28 was the 305 TPI. All Z28's were two-tone while the IROC-Z was mono colored. The IROC-Z had standard 16" wheels from 85 to 87, while the Z28 had 15". Fog lights were standard on the IROC while optional on the Z28 to the best of my knowledge. The IROC also had stiffer coil springs and larger anti-sway bars, plus the already mentioned wonder bar as an addition. In 1988 the IROC ceased to be an option on the Z28 and all Z28's were now IROC-Z's as the two merged.
Old Jul 5, 2005 | 04:17 AM
  #6  
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From: Illinois
Car: '91 Z28 & '90 RS Vert & '89 RS
Engine: 5.7L & none & 2.8L (soon to be LSX)
Transmission: yes
Axle/Gears: One's with teeeeefs
Originally posted by cdartz
All Z28's were two-tone while the IROC-Z was mono colored.
Is this right???? I have/had an '87 Z28 that was all yellow...top to bottom. It didn't have the IROC option and was mono-colored....
Old Jul 5, 2005 | 07:46 AM
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From: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
I guess it could be possible to order a Z28 in monotone, however most of them seem to be duo tone. There may may be a stripe delete option like they had on the Firebird and Formula. However from 87-90 I belive the Trans Am was NOT available without the lower stripe to my knowledge. The only way you could get a monotome T/A was to get the GTA. The same may be true for the Z28 but thats speculation at this point.
Old May 20, 2010 | 08:13 PM
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Re: Difference Between IROC-Z and Z28

can anyone help me? I am looking at an 87 iroc-z woth the 305 but on the rocker panels it says z-28 is this normal with this yera and model? it has iroc-z rims and vin #'s match up so please help
Old May 20, 2010 | 08:59 PM
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Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Re: Difference Between IROC-Z and Z28

Originally Posted by downey705
can anyone help me? I am looking at an 87 iroc-z woth the 305 but on the rocker panels it says z-28 is this normal with this yera and model?
Yes.

JamesC
Old May 21, 2010 | 10:34 AM
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From: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Difference Between IROC-Z and Z28

Someone correct me if I am wrong, but I think from 1985 - 1987 the IROC had a Z28 emblem on the rocker. In 1988 - 1990 since all Z28's were IROC-Z's then they got the IROC emblem on the rocker... Obviously the Z28 returned in 1991...

Also the IROC decal from 1985 - 1987 was toward the front of the door, in 1988 they moved it back on the door, thats if I remember it correctly...

I am a firebird guy, Scott would have a better idea than I but where is he?

John
Old May 21, 2010 | 11:27 AM
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Re: Difference Between IROC-Z and Z28

You've got it right John, the early Iroc's were based on the Z28, then in 88 all Z28's became Iroc's so the badge was changed to reflect marketing. Someone probably put two and two together and figured it was stupid to have two badges (that read the same thing) in the same area so they moved the decal back and started giving people the option to delete the decal altogether.

Don't forget that's also when the wheels changed. The style of the 16" Iroc wheel changed, and the base model 88 Iroc could be had with the 15x7 aluminum N90 Z28 wheel. In 89 they cooked up the 15" Iroc wheel styled like the 88 16" Iroc wheel, and that carried over to 1990.
Old May 21, 2010 | 03:04 PM
  #12  
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Car: 1992 Camaro Z28 1LE
Engine: 305 TPI
Transmission: 5-speed
Axle/Gears: G92 Perf. Axle
Re: Difference Between IROC-Z and Z28

Originally Posted by okfoz
I guess it could be possible to order a Z28 in monotone, however most of them seem to be duo tone. There may may be a stripe delete option like they had on the Firebird and Formula. However from 87-90 I belive the Trans Am was NOT available without the lower stripe to my knowledge. The only way you could get a monotome T/A was to get the GTA. The same may be true for the Z28 but thats speculation at this point.
I'm not aware of any way that one could get an '82 -'87 Z28 in monotone. Part of the "exclusivity" of the early IROC-Zs was that it was the only way you could get body-color ground effects.

I've never, never, never seen a monotone '82 - '87 standard Z28 that hadn't been repainted that way.

If someone has RPO sticker documentation of a factory "monotone" '87 or earlier Z28 I would be interested to see it.
Old May 21, 2010 | 03:46 PM
  #13  
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Car: Z/28..39 Plymouth truck in progress
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Re: Difference Between IROC-Z and Z28

This is the dealer brochure I got when I dealer ordered my Z/28 in late 84 and what it says about the "new" IROC............

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Old May 21, 2010 | 07:23 PM
  #14  
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Car: 87 IROC-Z, 82 Pace Car
Re: Difference Between IROC-Z and Z28

Yeah, JamesC, your response is to an old post, long before John knew about Camaros.

There was never a 3rd gen monotone Z28 available except on the IROC-Z and the 91/92s.
Old May 22, 2010 | 09:18 AM
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Re: Difference Between IROC-Z and Z28

As far as the steering box goes, I believe the only difference is the internal stops due to the wider 16inch wheels.
Old Nov 15, 2016 | 04:25 AM
  #16  
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Car: 86 Camaro
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: stock
Re: Difference Between IROC-Z and Z28

Hello everyone!

I dont know exactly the type of my car, because its customized, so I have two questions.

- Was the IROC-Z ever produced with rear drum brakes?

- The real main color is claret/dark red/maron. Was this colour ever paired with blue ground effects on Z28?


Thanks
Old Nov 15, 2016 | 04:56 AM
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Re: Difference Between IROC-Z and Z28

Yes a good number of Iroc's had drum rears.

And no, a red car would have either gray or gold ground effects.
Old Nov 15, 2016 | 07:19 AM
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Car: 90 Iroc Vert
Engine: 5.0L
Transmission: 700R4
Axle/Gears: 3.73
Re: Difference Between IROC-Z and Z28

Iroc's were made up until late 89, then Chevy lost the copy right to use the "IROC" name, so they made as many as they could in late 89 and titled them 90's. So in fact Irocs were made available up into the 90's year.
Old Nov 16, 2016 | 08:55 AM
  #19  
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Car: 91 Trans Am convertible
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Re: Difference Between IROC-Z and Z28

Could I ask on this thread the same question, but with regard's to the differences between the Trans Am and the GTA?
I've often wondered and studied pictures etc trying to find what the GTA has that I dont on my T/A, is it interior ? door cards etc?
Old Nov 16, 2016 | 03:22 PM
  #20  
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From: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Difference Between IROC-Z and Z28

The GTA was made From 1987-1992 the major difference are these
1) The GTA came Standard with the WS6, where the Trans Am came standard with the F41, with optional WS6
2) The GTA came standard with the L98, and the LB9 was an option, some years only the LB9 with the MM5, From 1987-1989 or 1990 the TA came standard with the LG4 (87) and LO3 (88-89 or 90), and optional LB9 or L98
3) The GTA came standard with the Ultima Seats, the TA did not
4) From 1987-1990 the TA came with fender vents, the GTA did not.
5) The GTA had Emblems, the Trans Am had Stickers
6) With the exception of 1987, the GTA was a loaded out Trans Am, kind of like the equivalent LTZ or the Denali of the TA, you could delete some things, and things like T-tops were optional, but the GTA had most of the the bells and whistles that were optional on the other cars.
Old Nov 17, 2016 | 07:19 AM
  #21  
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Car: 91 Trans Am convertible
Engine: LB9
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Axle/Gears: G80/GU2
Re: Difference Between IROC-Z and Z28

Thanks okfoz for taking time out to explain that, I love learning about 3rd gens.
Did firebird fender vents stop altogether in 1990?
Old Dec 4, 2016 | 07:54 PM
  #22  
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Car: Red, 1984 Z28 Camaro, T-Top.
Engine: 5.0: Engine 305
Re: Difference Between IROC-Z and Z28

,
Two Noticeable differences between the IROC-Z and the Z28.
-The first thing you'll probably notice that's different between the IROC-Z and the Z28 are the GROUND EFFECTS. On the IROC-Z the ground effects appear more aggressive than those of the Z28. You'll really notice the difference when comparing a 1982-1984 Z28 with a 1985 IROC-Z. The ground effects found on the face of the 1983-1984 Z28's contain holes, highlighted in black. The ground effects of the 1982-1984 Z28's are most often colored a different color from the car. In the 1985-1992 models of the IROC-Z, the ground effects appear larger and lower to the ground. The 1985-1992 IROC-Z's ground effects were also colored the same color as the car, making the IROC-Z's seem larger and lower to the ground than the Z28. The Ground effects on the front of an IROC-Z do not contain black highlighted holes as found on 1982-1984 Z28's

-The tires of the IROC-Z compared to the Z28's appear to be larger, and more aggressive than the Z28's. The stock aluminum rims of the IROC-Z measure 16" in diameter, and feature colors found on the stock striping around the car. The stock aluminum rims of the Z28 measure 15" in diameter. The rims on all Z28's are clear-coated with silver/grey inlaid color.
1984 Z28 Camaro
Old Dec 4, 2016 | 08:12 PM
  #23  
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Re: Difference Between IROC-Z and Z28

Kalum, you're comparing a 1982-1984 Z28 to a 1985-1990 IROC-Z. The differences in the early years versus the mid years is visually noticeable. The original post was how to determine the difference between a 1985-1987 Z28 and a 1985-1987 IROC-Z. Since the IROC-Z is an option package on the Z28, the OP was asking what the differences are on the IROC-Z.
Old Dec 6, 2016 | 12:16 AM
  #24  
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Car: Red, 1984 Z28 Camaro, T-Top.
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Re: Difference Between IROC-Z and Z28

Differences between the 1985-1989 IROC-Z Camaro and the Z/28 Camaro

"IROC-Z, THE ULTIMATE Z/28"-GENERAL MOTORS CO.

THE FOLLOWING ARE FEATURES OF THE 1985-1989 IROC-Z. THE STANDARD 1985-1989 Z/28 LACKED ANY OF THESE UPGRADED OPTIONS

-Fog Lamps and special IROC-Z badges inside and out, hood louvers and leather-wrapped steering wheel.

-Trim height and center of gravity lowered in IROC-Z.

-IROC-Z comes equipped with Quick-response power steering: 2.5 turns, lock-to-lock, with high effort valving for excellent road feel.

-P245/50VR-16 unidirectional high-performance tires, pioneered on Corvette. Tires mounted on 16" aluminum alloy rims with accent color, helping achieve .90g skidpad performance.

-Modified MacPherson-strut front suspension with increased caster for optimal steering response.

-Specific strut valving to provide excellent wheel control.

-Mass-efficient rear suspension utilizing Delco/Bilstein gas-filled shocks, two short control arms and a larger diameter stabilizer bar for impressive on-center axle control during cornering.

-Power front disk/rear drum brakes are standard: 4-wheel power disc brakes optional.


IF YOU ARE LOOKING TO INVEST IN AN F-BODY CAMARO FROM 1985-1989, AN IROC-Z IS THE BEST BANG FOR YOUR BUCK.

PRICES FOR AN IROC-Z AS OF 2016/2017 RANGE DOWNWARDS OF $8,000 TO UPWARDS OF $15,000-$20,000. THESE CARS ARE STILL VERY REASONABLE.
Old Dec 6, 2016 | 12:41 AM
  #25  
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Re: Difference Between IROC-Z and Z28

Ok, so this is a 6 year old post where the question has been asked and answered regarding the differences in the two models. Any additional answers at this time are duplicates.
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