Spring chart
 

courtesy of AndyZ28.
The link may help!
http://www.geocities.com/rgades/Sping.html?985231546900

It would be nice if you guys would look at your factory springs,and post what part# or code your car came with originally. ie;'89T/A has #????????

I finally got time to crawl under my '88 today and here's what I found out: The spring code on my rear springs is NNL, not apparent on the chart though. Didn't check the fronts..i'll let you know. Also, I tried to find the code on my rear end but I had no luck. I thought it was supposed to be on the front of the driver's side axle tube. I did find what appeared to be "G29F7" on the bottom of the "pumpkin"..it's a Borg-Warner and it's definately a posi. It also has a sticker on the diff cover that says "Austrailia" and "4ET". I'm just curious as to what gearing I have. AND I found an aluminum drive shaft which I thought only came on 1LE cars. Is this odd or am I just a bit ignorant with this stuff? Any help would be appreciated....Thanks..

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Ed Miller
Charlotte, NC
1991 RS,
bone stock driver;
1988 IROC L98
TPIS Fast Pack,MSD 6AL, Dynomax cat-back so far.

"Do you want to race or don't ya? I want to race." Dale Earnhardt

Ed,I will say that your rear> Is a 1987 2.77 posi B&W rear. With aluminium calipers W/12" rotors.ALA 1LE type. The aluminum driveshaft may have been installed by a previous owner.

The JG1 (Alum. Driveshaft) option was available to any IROC, it's possible the aluminum driveshaft was stock. My buddy has an 88 with one, of course he has a fully optioned car too https://www.thirdgen.org/messgboard/smile.gif

I say that because of the '87 rear in an '88 car. It "may" have been changed.

It wouldn't suprise me if the rear had been changed. I bought this supposedly "one owner, 41K original mile car" off of some people outside of Boston (first mistake) about 5 years ago when I was a little more naive than I am now. I found out that I had been duped when the DMV wouldn't reflect the "original" milage on the title. Then I found a piece of tape on the steering column that said "83 Camaro", a ton of broken glass under the rear seats, and other oddities here and there. I can only stress to guys purchasing cars to check every last detail..and don't trust people for sh*t. At least they were nice enough to leave me with an alum. driveshaft...cool.

The code is stamped on the front of the passenger side axle tube.

GH3 = 2.77
GW6 = 3.27
GM3 = 3.45



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1985 Yellow IROC-Z 5.0 HO, T-5 3.73 Torsen, 4 wheel disks
PFCM pads, GTA wheels, Koni yellows, B&M Ripper, Dynomax

I believe that 4ET would be, 1987 production 2.77 Borg-Warner.

Ahh, PASSENGER side, thanks for the info guys.

Ok, I finally got under the front..I have BZW springs, P/N 14029397, and my sway bar is DDH, P/N 14094339. Anyone know of a sway bar chart? I'm curious as to the size..but that mother is big! Also, I could NOT find a stamped rear end code on the passenger side tube.