There has been some debate about posi rears & disk brakes. Last night I finally checked my RPOs, and I verified that I do not have the G80 code. I suppose I should have checked for the disk brake RPO, but I have absolutely no reason to believe that the brakes aren't stock. So anyway... who else has disk brakes & an open diff?

 

I've got a 3.42 open disc rear in the 85 IROC...

Eric

 

same here open diff 3.42 10bolt with discs, in an 85 IROC, and they are all stock.

 

All 3 of us have the exact same combo in the 85s. I believe 85 was the last year that you could more or less mix and match from the option sheet, so I'm guessing that's the only year that an IROC could have been ordered that way.

 

I think you could still mix and match in 86. In 87 everthing changed to option packages, and posi became much more common because it was one of those manditory options.