Both of these cars are stock, and fortunately for sale. The IROC is 25 anniversary edition and is under $5000. The Z28 has 90K on it BUT its purple. The IROC is in OK condition but the Z is in great condition. Both are automatic. The main thing I want thing I want to know is which is faster, and how fast do they run. Also what are the hp & torque, average 0-60, and 1/4 mile.

94 Z28 5.7 275hp 325lbs of torque
I don't beleive they made an Iroc in 92 and 91 so it has to be a 90.

90 Iroc LB9 210hp 285lbs of torque
90 Iroc LB9 230hp 300lbs of torque
90 Iroc L98 5.7 245hp 345lbs of torque

hope that helps

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1988 Sport Coupe 305 TBI
K&N
Flowmaster exhaust


Daily driver:
1988 K1500 5.7 4x4 shortbed flowmaster cat-back gutted cat.
AOL: RyanNH84

25 Anniversary Edition IROC huh? Thats pretty rare, I would keep that garaged if I were you.

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1992 Camaro RS
5.0L TBI
K&N Airfilter and ready to take on the world!
My 1992 RS

The IROC-Z was only produced from 1985-1990.

Moter Trend got 0-60 in 5.8 and 1/4mile 14.4@97 out of a 3600lb 350 3.23 geared IROC coupe..They have been known to be even .2 faster.The auto Z's with 3.23'susually run high 5's 0-60's and low 14,high 13 1/4's.The 2.73 geared ones are about .2 slower.0-60 its dead even,but the LT1's better breathing and 30 Xtra hp will start to pull away.

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1990 Trans Am GTA,Black/Black Leather,350,auto 3.23,Dual Cats,
SLP Package,Fastchip,GSC's,Brand New Trans with Corvette 2400 stall,Servo/Shift Kit
G-tech 1/4mile(before trans and roasting 1st)13.6@104,now probably 13.2@track with traction/good conditions
stock(track)14.3@96
member www.transamgta.com
Previous Thirdgen
1986 Camaro IROC-Z

NHcamaro's numbers sound right to me, and like the other guys said, there is no 25th aniv. IROC, after the 90 1/2 model year they stopped making IROCs. Unless somone is a faker and put IROC stickers on a 92Z which is always possible! IMO the LT1 is a much better engine in original form and also responds to mods better. I also like the "power programmers" you can use on 4th gens as opposed to having to burn chips. It has the 4l80E(?) tranny which is much better, and the programmer i mentioned also lets you adjust shift points electronically. BUT, if its a blander looking 4thG, the IROC or Z whichever it is will look cooler and be not too far behind it in performance. I'm not a big fan of purple cars either, but every now and then i see a kewl one. I'll stop running my mouth now!


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88 Camaro (not an RS, or an IROC, justa camaro.)
305TBI/700R4/2.73
14" Open Element and Flowmaster 80 seires

Next up: headers and gears

No actually, they have 4L60E trannies, but those are still alright too. Better watch out for those auto cars though, they come with 2.73 gears just like the older cars. If I were you I would buy a LT1/6-speed, those are really quick. I wouldn't really go for the Auto cars though. But if you want decent performance, and looks...get the 4th gen....if you are a moddin' fool, get the third gen. Just my 2 cents.

-ws6formula-

Quite alot of 4th gen auto cars have 3.23s, which was an option. Noticeable improvement, but a LT1 auto vs a late L98 auto is a fairly close race in the 1/4 mile either way.

There is no 92 IROC like others have said so who knows what this car actually is or what engine it has. It could be a Z28 or only a RS, we're all kinda assuming it actually is a Z28 and will have a 350 TPI. That's not a given. If it is not a 350 it's going to be noticeably slower unless it's a 5spd with the dual cat 305 TPI. If it's not a Z28 you don't want it, the RS will be godawful slow compared to the Z28, not to mention tmhe 4thgen Z...

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

4L60E, 4L80E. Are pretty much the same damn thing. The '80 is a little tougher but the '60 is still plenty good. Anyway the real info.
4th Gens were based on a platform that was derived from the 3rd Gens. The have very similar floor pans subframes and all the fun stuff that goes along with that. The big differences are the front suspensions and the cowl and engine compartment.
A 4th Gen uses a Double A-Arm front suspension with a shock and coil spring. This is the superior to the 3rd Gen strut, lower A-Arm and coil spring setup. Do not get me wrong the 3rd Gen setup is still good plenty good it is just that the 4th Gen is better.
The engine compartment is very different on the two cars. The cowl on the 4th Gen slopes down over the 7&8 cylinders on the engine. This and the fact everything is crowed from all the other goodies makes even routine maintence a pain in the rear. I have never done this but I am told the easiest way to pull the engines on a 4th is from the bottom. You drop the whole front suspension and engine right out the bottom with a lift. This is obviously beyond the means of the normal enthusiast. That is the reason a 383 stroker 3rd Gen is decently common and almost unheard of with a 4th Gen.
In short if you want out of the box performance the 4th is the way to go. You can still do little mods to it but just changing sparkplugs becomes an adventure and takes half of a day.

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84 Z28 383
Stripped w/Cage back halved w/ladder bars and coil overs and 9 inch
700R-4 3.73

[This message has been edited by Chronos_Titan (edited August 01, 2001).]