- The RPO code was B4Z
- Base Engine:
LG4 "Quadrajet" Carbureted 305 CID (5.0L) V-8
- Optional Engine(s):
L69 "Quadrajet" Carbureted H.O. 305 CID (5.0L) V-8
LB9 Tuned Port Injection (TPI) 305 CID (5.0L) V-8
- Colors available were White, Black, Bright Red, Yellow Gold, Bright Blue and Dark Red Metallic
- A 'unique' feature of the 1986 IROC-Z, is that the third brake light was located on top of the hatch window, close to the roof. Later year, base model Camaros had the brake light in the same location as most did not have a rear spoiler.
The only way you can use the VIN to tell if it's an IROC is the 88-90 cars since there was no Z28. 85-87 cars were just RPO's. So if you don't have the RPO code (should be in the glovebox), you can take your VIN to the dealership and they should be able to get you a list of RPO codes.
go to thirdgen.org they got a butt load of info on third gen the rpo skicker should be in ur center box will tell u everything and thirdgen.org has rpo decoder thing but look for b4z is the iroc pkg. and 88-90 irocs will say z28 because there was no z28 in those years just iroc u should have z28 and b4z and i dont know this for sure but i know 87 and up all irocs had the 145 speedo dont know for sure about 85 and 86 i think its the same way and irocs came with leather wraped shifter and e brake if this helps u out