85-87 There was an IROC-Z and Z28

88-90 All Z's were IROCS

My friend has an 85 Z28 body/frame, and a 92 RS hit in the front w. good interior

I have a 350 Shortblock bored .30 over with a ZZ9 Cam, were thinking of "combining our assets" into one nice car.

I was under the impression that during the IROC production there were no regular Z's. But from what I have found recently I guess that only stands true for 88-90.

Either way if its a Z or an IROC were gonna build it.

 

You are basically correct.

85-87 The Iroc was RPO code B4Z, Available as an option on the Z28.

88-90 the z28 was dropped and Iroc was no longer an option but a model. RPO code B4Z was dropped and RPO code Z28 was kept.