im looking at an 88 and i dont know if its an RS, Z28 or IROCZ28 i have the vin number

 

Look for the B4Z RPO code on the SPID label inside the center console between the front seats.

 

you cant tell anything from the VIN?

 

Not really. It could tell you that it's not an IROC if it says that the original engine was a V6, but that's about it.

 

its a 305 V8 but there are no badges on the car except the z28 license plate holder

 

As Aperion stated look on the SPID decal on the console door(make sure the VIN on it matches the car's VIN)for B4Z and Z28.In '88 RPO-Z28 was part of RPO-B4Z.There was no separate Z28 model from '88 to mid '90(and technically no '90 models).
The VIN will only tell you what motor she came with from the factory.The LO3(TBI 305 VIN eighth digit "E") was standard in the IROC and optional on the RS.The LB9(TPI 305 VIN eighth digit "F")and L98(TPI 350 VIN eighth digit "8")were available only on the IROC.If the VIN eighth is a "S"(LB8 173 V6)then as Aperion stated it's not an IROC.
Also look on the door decal for tire size.15" was standard on all models.But in '88 16" was only avalable on the IROC coupe and convertible.

 

Every Camaro with GFX has the 'Z28' license plate bracket. Being an 88 it's either a RS or an Irocz. Since there was no middle ground, the Irocz package doesn't mean as much as the equipment on the car. You could put a 88 V8 RS next to a 88 Iroc and they could be nearly the same car with only badges and minor suspension upgrade changes on the Iroc.

Just look for the upgraded equipment, 16" wheels, wonderbar, graphics, etc.

 

well shes the E Car

 

305 TBI, then. Could be an RS, could be an IROC.

 

Two people above stated to look for the RPO code B4Z. That is incorrect for '88. That code was only used from '85 to '87. You will only find the Z28 code since by default a Z28 was an IROC-Z in '88.

 

If he has the RPO decal in his console (and it's the correct decal to the car), an Iroc in '88 wouldn't have the B4Z (as in '85-'87), just look for the Z28 RPO.

Other hints (all things being original). . .
- the IrocZ's had black headlight buckets while the RS was same as the body colour.
- in '88 the IrocZ came standard with 15" wheels or the now optional 16" inch double "spoke" (new for '88) wheels. So size of wheels leaves things undetermined.
- in '88 (correct me if I'm wrong) the base Camaro's ground effects were still different than the body's, being silverish (as opposed to the body coloured '89's) while the IrocZ's were always the same colour as the body.
- didn't the base Camaro have the regular hood while the IrocZ got the louvered hood?
- if your car has the Aero rear wing, RPO D81 (which was unique for '88) then it's a base Camaro. However, later that year it changed to get the same D80 rear spoiler that the Iroc's had.
- didn't the '88 base Camaro's tailights have the one thick line through the middle resulting in 6 rectangles while the IrocZ had two thin lines resulting in 12 rectangles?

Just a few more possible ideas. Let me know if I'm off on anything. Been a while since I've seen the two side by side.

 

Well I thought all the Irocs were TPI in 88(either 305 T5, 305 auto or 350 auto if I recall) and the RS was the V6 or the 305 TBI's

Again though like they said above the Iroc will have the wonder bar, dual fans, and a Posi rearend (tricky part was it came as the alumium drum or disc on these cars)

 

An IROC could be any V8.

 

[QUOTE=Drew;3317831]Being an 88 it's either a RS or an Irocz. Since there was no middle ground, QUOTE]

There was an 88 SC with factory GFX

 

That's a great point Iron Duke on the '88 Sport Coupe.Chevrolet cut the line to 2 models technically as the RS was more a regional package for '88.Technically they were all Sport coupes or convertibles as RS and IROC were options on it(as it had always been with the Z28/IROC).I stand corrected on B4Z being on the SPID in '88 but Z28 will be.But as I stated the VIN will definitly indicate a IROC if the eighth digit is F(LB9)or 8(L98/B2L).Those codes(LB9 or L98 and B2L)will also be on the SPID.Just about everything else visual can be added to a V8(VIN eighth digit E -LO3)Sport Coupe/convertible to make it look like an IROC.But the tire decal will give it away as 16" wheels were only available on IROC models for '88(unless it's missing).Positraction(G80) and 4 wheel disc brakes(J65)weren't a standard part of an IROC(and they could be ordered on a SC/RS)>

 

Something that's been missed is the 16" rims were not standard on the IROC-Z in 88. The best way to know is to have the engine code or Z28 on the SPID. Too many other variables could have changed over the years as parts are easily swapped.

 

That was mentioned already in my post above (back on April 25).
Good point anyways.