I recently bought a 86 IROC. It is yellow, has a TPI 305 and and auto trans. It did not come with the RPO's and i cannot find them in the car. I t also has 4-wheel disc brakes and a 3.23 rear end gear. The RPO for the 3.23 gear is G92. I looked and was not able to find an engine oil cooler. Is the G92 option in 86 only the rear end gear or should it include 4-wheel discbrakes and an oil cooler like in 87-90 IROC's?

 

Yes, in 1986, all options were still ordered seperately. So G92 in 1986 denotes performance axle ratio only. In 1987 G92 became a package option that included, engine oil cooler, disc brakes, etc.