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The G92 Performance-Optioned 3rd Gen Camaro (Not Your Typical IROC-Z)

John (Trae) King's rare 1990 G92 optioned Camaro with the 230hp 5.0 LB9 TPI 5-speed and the DX3 Decal & Stripe delete option.

John (Trae) King's rare 1990 G92 optioned Camaro with the 230hp 5.0 LB9 TPI 5-speed and the DX3 Decal & Stripe delete option.

1990 G92 code IROC-Z Camaro

1990 G92 code IROC-Z Camaro

Many believe that 1985-86 ushered in the rebirth of American Performance. With the introduction of GM's 5.0 liter 305ci small block TPI (Tuned Port Injection) and Ford's 5.0 liter 302ci small block EFI, the High-Output Ponycar war was in full force again.

By 1990, and with GM tired of the lighter 5.0 LX having its way with the Camaro and Firebird on the street and track, the G92 option was offered as a full "Performance Package" rather than simply a performance axle option (as prior to 1990) with G92 consisting of multiple performance upgrades and weight-saving options, and the manual 5-speed cars getting a revised and more aggressive camshaft that raised the 5.0 liter engines to 230hp.

GM and their F-body twin Ponycars were finally getting the upper hand on the street and getting revenge for all the 5.0 F-body automatic cruisers that were getting picked on by the infamously quick Fox-Body platformed 5.0 Mustang. The G92 code was GM's Ace up its sleeve! But Ford also had a secret weapon, the low-optioned and stripped down 5.0 LX Coupe (notchback trunk edition models) that could run documented low 14 second quarter mile times, almost a half a second faster than the heavier and more common 5.0 LX hatch models, and almost a full second faster than the fully optioned and few hundred pounds heavier 5.0 Mustang GT. The only chance GM had against a 3,000 lb 5.0 liter Mustang LX Coupe (notchback) was the "trimmed of all fat" and low-optioned, 3,100 lb ultra rare 1LE code Camaro. Motorweek tested a 1989 "bare-bones" 1LE optioned Camaro to the tune of a 13.9 1/4 mile time!

The 1LE was a special order Camaro reminiscent of the legendary COPO Camaros of the first Musclecar era. A very limited production Camaro that was GM's answer to the road racing Saleen Mustangs that were dominant on the showroom stock circuit. To order a 1LE performance optioned Camaro or Firebird, one had to know their way around an order sheet. By checking off the right items, you could get the hottest Camaro or Firebird to date. You had to simply order the "G92 performance package" and delete the creature comforts of air conditioning with the "C41 AC Delete option," which gives you the standard heater option. This triggered the "bare bones" version, 1LE Road Racing Performance Package. The 1LE option appears on the order sheet as a $675 "Special Performance Package" and consists of:

  • Twin Piston Z51 Corvette brakes
  • Aluminum Drive-shaft (prop)
  • High-Flow Exhaust (dual Y-pipe w/ dual catalytic converters)
  • Re-calibrated Engine PROM
  • Performance Axle Ratio (5.0 = 3.42 | 5.7 = 3.23)
  • Hardened Axles and Gears
  • Engine Oil Cooler
  • Special Swinging Fuel Baffle (prevents fuel starvation during hard cornering)
  • Special Calibrated Shock Absorbers
  • Fog Light Delete
  • Weight Saving Options
1990 G92code Camaro vs 1989 5.0 Mustang GT. A lighter version 5.0 Mustang LX would be a better match-up against this 3,200 lb IROC sleeper.

1990 G92code Camaro vs 1989 5.0 Mustang GT. A lighter version 5.0 Mustang LX would be a better match-up against this 3,200 lb IROC sleeper.

A rare optioned 1990 "G92code" Tuned Port IROC-Z Camaro with the DX3 (decal & stripe delete) code, and also the GU5 code (3.42 gears) and N10 (performance exhaust) and a few other goodies.

A rare optioned 1990 "G92code" Tuned Port IROC-Z Camaro with the DX3 (decal & stripe delete) code, and also the GU5 code (3.42 gears) and N10 (performance exhaust) and a few other goodies.

The 1990 model year, with manual 5-speed and equipped G92 and 1LE packages, included the fastest production models of the 1985-90 five liter (305 cubic inch) version IROC-Z model years, as is the 1991-92 Tuned Port Injected Z28 models (as the IROC-Z ended in 1990 and replaced with Z28 in 1991). Here is more 3rd generation F-body knowledge and facts for 3rd gen newbies and/or Camaro enthusiasts looking for research, facts, specs, stats, and information on the 3rd generation Camaro and Firebird.

Starting with the 1985, and the first year of the Tuned Port (TPI) system, actually outperformed the five liter Mustang GT in Motor Trend's magazine road testing in 1985 (this wasn't simply based on straight line performance) and Motor Trend crowned the new Tuned Port Injection (TPI) IROC-Z to be the Ponycar king of the 1985 production year... the other hot performance optioned 3rd gen was the L69 H.O model which could be ordered with the 5-speed. The 5.0 Tuned Port Injection models could not be ordered with the manual tranny until 1987 (due to the high torque ratings of the Tuned Port Injection), which was also the first year for the new Corvette 5.7 TPI (L98/B2L) engines fitted in the F-body twins. But they, too, could not be ordered with manual transmission.

In 1986 GM changed the camshaft design for emissions purposes and lost power in the TPI engine from this cam change. Motor Trend's testing documented the 5.0 Mustang absolutely destroying the 1986 TPI Camaro IROC-Z and Z28 in road testing comparison. GM changed Camshafts the following year due to this lack of performance. The 1986 Tuned Port Injected Camaro was the least powerful of the 85-90 IROC Camaros, and road testing revealed the embarrassing 1/4 mile times for GM's Ponycar twins that particular model year.

1987 was the much-anticipated release of the Corvette L98/B2L 5.7 liter 350ci TPI motor for the Camaro IROC-Z, Formula 350 and GTA Trans Am. Motor Trend testing showed disappointing results for the 225hp 5.7 TPI Camaro with its identical 1/4 mile dragstrip times as the 5.0 EFI Mustang... handling & braking went to the LB9 optioned 5.0 powered manual 5-speed Camaro/Firebird as usual, thanks to GM's more advanced suspension geometry and braking components over Ford's weaker handling/braking 5.0 liter Mustang. Both the 5.7 TPI Camaro and 5.0 EFI Mustang recorded identical 14.7 quarter mile times and 140+mph top speeds with the Camaro edging the Mustang out slightly over 100mph due to its aerodynamic design.

1988 the Camaro and F-body cousin Firebird horsepower rating went up, as it did every year after... until 1990 where the TPI maxed out at 245hp for the 5.7 (L98) 350ci automatic and 230hp for the 5.0 (LB9) 305ci 5-speed with G92 and 1LE options (limited 1LE option F-bodies were built to compete with the Saleen Mustangs in showroom stock road racing competition) with documented 1/4 mile times of 14.6 for the 5.0/5spd model and 14.4 for the bigger 5.7/auto model, shows these were the best performing and fastest 3rd generation F-bodies produced to date. (Take note that this is not the TBI [Throttle Body Injection] 170hp Camaro or Firebird, as they were the "economy version" and had around 75hp less than the performance version 245hp TPI [Tuned Port Injection] equipped F-body versions, which was a big contrast in performance between the TPI and TBI models.) There were only four (6) 1LE models produced in 1988, with over 700 units being produced by the last year of the 3rd Gen run in 1992.

1989 and 1990 would prove to be the best performing IROC-Z models of the 3rd generation models. In 1990 the G92 option became a full performance "street" package that shocked many unsuspecting 5.0 Mustang of the time, with 230hp and 245hp, 3.23 gears or 3.42 gears, and similar 3,200 lb weight, the 5.0 Mustang guys were quickly finding out that these G92 optioned performance Camaros were a different breed from the earlier run-of-the-mill cruiser models.

Now, a note for all the newbies and/or young fellas new to the 3rd generation F-bodies, or those who may be thinking about restoring or building up a late 1980s early 1990s 3rd generation Camaro, Firebird Formula, or Trans Am. Just remember that TPI = good and TBI = bad if you are looking for horsepower or wanting to run with 5.0 Mustangs of the same era. The TBI will not get it done in factory or semi modded form. You will need at least the LB9 optioned 5.0 TPI with the manual 5-speed or the L98 optioned 5.7 automatic (the 350ci cars were not available with the 5-speed transmission, only the 4-speed automatic). Also remember, factory stock for stock trim, the 1986 was the slowest year of production, and the 1990 IROC-Z and 1991-92 Z28 models were the most powerful 3rd Gen models, although the 1991-92 cars carried a little extra weight. Pound for pound the 1989 and 1990 IROC-Z and Formula were the best performing 3rd Gen models produced (of course that does not include ultra-rare models like the anniversary turbo Trans Am or SLP Firehawk).

The author of this article owns both Camaro and Mustang models from this generation, and I love them equally. But honestly, I believe that the Ford 5.0 liter 302 engine is a better all-around motor versus the GM 5.0 liter 305 engine. In terms of a balance of power, torque, reliability, dependability, acceptance to bolt-on modifications... and even sound. The motors are very close in specs, but the 302 has a larger bore, and many people don't realize that the Ford 302 actually has the same size four inch (4") bore as GM's ever-popular 5.7 liter 350ci small block, but the Ford 302 has a shorter stroke compared to GM's 305ci small block. Another positive of the 305 is the fact that is almost a perfect square balanced motor, where the bore and stroke are very close to being equal, similar to Ford's durable 4.6 liter (281ci) engine, which produced a little over 300hp (naturally aspirated) in its final production years and 400hp (forced induction) in the legendary "Terminator SVT Cobras." The 305 unfortunately is remembered for all the non-performance economy versions through the years, which is a shame because the 230hp 5.0 liter 305 was a great little motor, and if weren't for GM guy's having the option for a larger displacement 5.7 liter 350 engine to turn to, the little 305 would have had the aftermarket support and loyal following just as Ford's little 302.

The featured white Camaro IROC-Z in this article is owned by the author, I figured I'd put that out there so you can't call foul by way of bias, towards the Mustang. These claims are simply my opinion from the years of experience I've had with these cars. As stated earlier, I have an equal love for both of these domestic Ponycars. Asking me to choose between Camaro and Mustang is like asking me which one of my kids I love more! Certainly there is something good as well as something bad with both models. If I had to vote, judge or award these cars from this era, I'd have to give straight line "Dragstrip" power, torque and performance to the Mustang, and the "Corner Carving - Road Racing" abilities of handling and braking advantage to the Camaro/Firebird.

So there you have it, some random American Musclecar opinions from John @ nedaCFilms / Mustang-Town and V8ponycars.com. And you know what people say about opinions—they are like !%$?&!

Thank you for taking the time to read my article. I hope you found some information to be useful. Feel free to ask any questions you may have by commenting below. Now, go buy American!

Car Craft magazine Dec. 2006

Car Craft magazine Dec. 2006

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


Aaron Justin van den bemd on September 10, 2019:

Nice article ,great to learn more about the iroc z28,i had a 1974 lt 350 a few years back and now looking at a 3rd gen z28 thanks for the great write up.

John on June 22, 2017:

Me and my son have a 92 formula Firebird with a 5.7 and the WS6suspension package

chris Edgecomb on December 14, 2016:

Nice Camaro I own a odd duck its a 1987 IRoc with the 5.7 has no t-tops no air and no power windows and locks has the G92 option and the z51 brakes, eng oil cooler if I don't have a one 1LE then what do I have? it also has a special dealer order code

buddy vest on June 14, 2015:

I have just recently purchased a true 1989 Camaro iroc-z with the 350-tpi and rear disc brakes, also this car was ordered loaded including, power mirrors, and power seat. could anybody please tell me how many of these were made? also i think i might have one of the 1,428 iroc-z's made that year, also how can I tell if it is or not!...Thanks a lot!

dee dee... on January 27, 2015:

I have a 1991 z28 white... very nice.. auto... wish it was 5speed

Nick Brunner on May 17, 2014:

Hello to every one

I have a question.

for many years, i want to finde out how rare is my,

1990 camaro iroc z

powered by 5.0 and manual 5-speed

how rare is it ?

i haven`t seen an other one!!

thanks for an answer

best greetings from switzerland

and sorry for my english, but i went to come to the USA, learning better english ;)

trip garcia on March 16, 2014:

I hav an 88 camaro. was told dealer gav the opt of the 350 but its manual. I believe it's a 305 though, anyway is it hard to change a tbi to a tpi???

James on July 31, 2013:

Love this video and write up! As fans of both cars, I appreciate your opinions of both the strengths and weaknesses of these 80's pony cars.

I have an L98 powered GTA and am quite smitten with the ole tune port. However, Is it a lost cause to try to modify a stock 305 TPI? I'd love to own the right 5.0 5-speed one day but would love to try the 305 TPI 5-speed before reverting to my old ways.

Furthermore, I had no idea the 5.0L ford had a similar bore to a SBC (or SBO for that matter). Keep rocking the cool car vids and write-ups.


1LE 350 Tpi on March 12, 2013:

I just purchased this car a month ago found out it is 1 of 182 made its a 1991 and has every after market bolt on you could do with out a cam or headers, I hear a lot of people talk crap about them being gutless well from a dead stop it will eat my buddys 2012 2ss 6.2ltr unless you turbo charged or used nitrous on a mustang 5.0 notch or build the hell out of the motor it would humiliate it.

zr1zora on September 29, 2012:

i owned a beautiful re on red z28 l98

Jay on September 17, 2012:

These were the only 3rd Gens that could hang with the 5.0 Mustang, period.

larry_anderson_911@hotmail.com on July 23, 2012:

i would like to know how many 1991 5 liter tune port cameros they made? thanks..i have one with the big spoiler p/w p/d p/t 5 speed. 30,ooo miles on it!! love the car!! thanks!!

nedaCFilms (author) from East Coast Mid Atlantic on March 14, 2012:

I totally agree with you... I could never own an automatic performance car, a manual transmission just gives so much more torque and RPM control. And, as you stated you don't lose as much power through the drive-train.

Darrel Apel on March 13, 2012:

I have a 1987 i-roc 305 TPI T5 5speed never really liked these cameros till now the manuel trans makes all the difference I own a transmission shop in ca. you get more horse power to the rear wheels with the manual than a automatic and the rating from the 5.7 and the 5.0 is only about 15 horse power that is easly used up though the automatic before it gets to the rear wheels (for me manuel over automatic any day) and really neither of these transmission are junk

Chris on January 12, 2012:

An 85 305 tpi 5 speed? The 85 had 215 hp and would def keep up with an 88 5.7 if u know how to drive it right. Even the very early 86s had 215. Such as my 10/85 that found a 3:42 and 6 speed ;)

Eric Bryan Walker from KANSAS CITY MISSOURI on December 30, 2011:

All right Buick fans. I have a 1986 Grandnational! The Indy car TA must be awesome. With the engine matching what i have in my car. The fluxuating horse power is incredible. This car will have a hub written about it, and if i could get some feed back for a beginner writing my first hub. Feedback is appreciated, THANKS

Eric Bryan Walker from KANSAS CITY MISSOURI on December 30, 2011:

Hey , i had a chance to drive a true IROC and im not sure what year it was but the car must have had the corvette 350. I was given an hour or so to drive and the car i drove back in 1987 had incredible performance and i would love having one of the same caliber. That's the only Iroc ive been privelaged to drive. Some are great!

Matt on August 11, 2011:

Hi, I am an owner of a 1988 IROC-Z28 L98 350 TPI. I came across this article and saw the stills above from a video that I saw on Youtube. I'm actually a subscriber to the "NedacFilms" channel. I saw the comment made by "FredY" and I'd have to respectfully disagree with his comment. For one thing, the only 305 TPI's that could come close to a 350 Auto/TPI was the 5 speed's with the G92 code. The G92 option was available before 1990, as it was in 1987 as standard on the 350's and as an option for the 350's in 1988 and 1989 I believe. The 1988 IROC 350's got worse times as tested back then because GM put 2:77 gearing in them and it's possible testing conditions were different each time also.

The G92 3:27 POSI upgrade from a 2:77 ratio makes a lot of difference in times and acceleration from any speed, especially a dig if you have traction. The 305 TPI's honestly are some of the biggest junk motors GM ever put in a Camaro. The 305 TPI had nothing on the 350's back then and only the 305 TPI G92 optioned with a 5 speed came close to one as far as 1/4 mile and 0-60 times go. The T5 transmissions in those 305's were junk but the 700r4's from 1987-1992 were decently built transmissions for what they were being used in (the L98's).

Overall, on an average day, the 350 TPI bone stock in healthy shape will eat a 305 TPI auto/5 speed that is bone stock. Sometimes it's possible the 5speed 305 may win but it'll be barely or very close. 305's didn't get decent power until the early 90's right before the 3rd Gen. era came to an end. Either way I'm proud to have a 350 mildly built TPI/L98 Camaro and I've yet to have lost to any 305 car.

fredY on August 08, 2011:

I'm driving a 1989 Trans Am (not GTA) with the 5,0 manual @230hp and i'm pretty sure i overrun any 5,7.

By the way, great IROC!

Steve on February 02, 2011:

It's good to see these cars finally get recognized for what they truly are,the "musclecars" of my generation.I was a child of the 80's and a Chevy lover,my attention was always on the fact that the 'Stang had it all over the Iroc.Every year i'd wait for G.M. to up the horsepower so we could finally beat the Ford.In 1990 i got my wish.I'm the proud owner of a '91 Z28 G92 optioned car with the 5.7 and i love it,what a torque monster!I'm now looking for an unmolested '87-'93 Mustang to go along with my Z28.Imagine these two once rivals parked next to each other in my garage!Thanks for the info on these great cars!

robert m on January 24, 2011:

nice site.i'm an slp buff third gen firehalk very cool.saw the slp promo on youtube they planned to build 500 halks in 92.sold only 25 yep rare.what brought me here was the DX3 option code .i recently sold my 87 iroc 5.7TPI red it had no door decal & said iroc in the ground affects just behind the front tire i was the third owner and met the second claimed it was some rare "delete option" it was a late production car 127Ksomething could that car have been somerthing special? thanx robert...

Trae King (nedaCFilms) on January 15, 2011:

Hey Brasky, you are correct that the Turbo Trans Am was faster, as was the fastest 3rd gen of all time being the 1992 Firehawk. But these cars are very limited edition and so rare that you never see them... maybe in a collection somewhere. The 1LE and G92 cars are actually still running the streets and competing on road courses across the country every weekend.

Brasky on January 14, 2011:

Great looking IROC!! I have to disagree that the 1LE 350TPI cars are the fastest 3rd gen F-bodies. That title would go to the 1989 Indy 500 Pace Car Turbo Trans Am with the 3.8 turbo V6 borrowed from the Buick Grand Nat. One of these would easily spank a TPI F-body or 5.0 'stang assuming all cars are stock.

Trae (John) King on November 13, 2010:

Hey Camaro-Mustang fans... if there is particular information about these cars that you are interested in, just post a comment, and I'll publish a HUB on/about the information you are looking for.

~Trae (John) King @ nedaCFilms

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