BigSmallBlck2GZ

Not really a stupid ??, jus dont know the answer...What does the Z28 represent in my 2000 or any year z28 for that...know what ss is and rs, jus havent figured out the z part...let me know..

8-Pack

Z28 is an RPO (option) code, It dosent stand for anything like SS or RS. Same thing with WS6.

VIP1

This can get really long-winded if you want the history of the Z28.

I started in 67 or 68. It was basically a street version of Chevy's race car to compete in SCCA Trans Am Series (Pontiac had the Trans Am and had to pay royalties to use the name). They made it to satisfy homologation rules. I dont remember the suspension and tranny but it had a 302ci V8 that liked to rev. If I remember correctly they either used a 283 block and 327 crank or a 327 block and a 283 crank to get that displacement. The rules at the time had a 5L limit (305ci).

Over the years the Z28 RPO has changed to mean different option packages and was basically the base V8 model in the 4th gen.

Quick note, there were a few years in the 80's (the 3rd gen body) where there was no Z28. They made the IROC to take its place. I dont know the why/how/etc of that one.

This is from memory, if anything is wrong please let me know.

Swang

iTrader: (3)

it started in 67. the z28 was the DZ302 that they rated at 290 horse 290 lb torque. it had suspension upgardes but a big part of what it had were front disc brakes standard. however...most think that the 290 hp rating was a little low. i know a guy who had one who could outrun a hemi charger until 4th and he only lost by a couple lengths. damn good running car. the first year in 67 all the intake and such was done by edelbrock because GM hadnt started mass producing parts yet. also if i remember correctly it had a tachometer standard.

about the IROC. it was called the IROC z28. so ther was always a z28.

VIP1

Looks like you are right.

IROC-Z History:
http://www.iroczone.com/history.htm

Camaro History:
http://www.edmunds.com/insideline/do...rticleId=66170

BigSmallBlck2GZ

Rite on guys, no one could ever give me a straight answer, so i didnt know if they where right or jus blowing smoke....still wonder why the letter z and 28 for numbers... its mind boggling

warpwr

Yep. Z24 is a Cavalier for example. I think one of the Chevy pickups goes by its RPO also. And I think Corvette too.

badSol

Z51 for the trucks

byrontaylor

I thought the trucks were Z-71, and the upgrade was pretty much a push-button 4x4, a skid plate, and most have the bigger engines, the 5.3 vs. the 4.8 in 1500 series, and 6.0 vs. 5.3 in 2500 series (not sure about the 2500 series so correct me if I'm wrong)

Also I believe the s-10's had an RPO code ZR-2 that was for a suspension upgrade, I think it was only 4x4 but again I'm not too sure.

The cavalier's Z-24 was also suspension I believe. I am pretty sure it still had the ecotech 2.2L engine.

The Avalanche has a Z-66?, and a Z-71( again with a skid plate and push button 4x4), and I believe both the 5.3L standard with an option of the 6.0L, in this truck I do not believe that the Z-71's came standard with the 6.0L, the 66 I believe is 2wd, and the Z-71 is 4x4 I think...again not 100% sure on that either. They may not even be RPO codes, I don't know.

Correct me if I'm wrong please...Thanks

Byron

badSol

You're correct, I'm stupid.

Z51 is an option on Vettes, Z71 is on the trucks...

Also, I don't believe you can get the 5.3L in the 2500's, starts at the 6.0L, then the 6.6L Duramax, and I believe recently they added the 8.1L.

byrontaylor

I don't know jack **** about the 2500, that's just what I always thought I guess...You learn something new everyday...I didn't even know you could get the 8.1 in a 2500, thought it had to be a 3500...I just can't keep up...my hard drive up top is running out of room. Have to send it down below now, I don't use that for anything anymore...lol

GoldenBird

This is actually not true and you can read more about this if you check out the "1988" heading in the link VIP posted.
For whatever reason, I'm pretty sure "IROC-Z" was a marketing package added to most 84-87 Z28's. I think some Z28's didn't have the IROC-Z package these years, but at the very least every IROC-Z was also a Z28.
GM threw a curveball however, and made some weird changes to trim and whatnot for 1988. Most notably adding gfx to a base Camaro for the first time, which is the only year a base thirdgen Camaro has groud effects, but is not called an RS yet. They also dropped the Z28 package, but continued to call the higher end V8 model "IROC-Z". These cars wheren't both- just IROC-Z. They didn't bring Z28 back until 1991, at which point they dropped the IROC-Z designation. It's really confusing, and took me years to get them all straight- but I'm pretty sure that's the rundown. If I'm wrong in some way please let me know.

byrontaylor

Just so ya know....IROC=International Race of Champions

You prolly already knew but oh well