Hi I am refurbishing a set of 85-87 16 inch Iroc z wheels. I know that the rear wheels have a 12mm offset or so. I fitted the wheel on the hub and it seems like the wheel is close to the rear bumb stop and emergency brake cable. Clearence is about an inch with only the wheel ( no tire). Has anyone installed the 85-87 iroc wheels on a drum rear without clearence issues? BTW my car is a 1988 iroc z with the drum rearend.

I believe the IROC-Z's with drum rears came from the factory with 3mm slip on spacers for the rear only.

Non-issue. More about the spacer from the 10-Bolt FAQ:

Why Does My Rear Have Spacers?
The spacer was apparently used on 16" wheels when GM switched from aluminum to iron drums, which created a .187 size difference. The spacer, however, seems to be hit or miss and essentially unnecessary. Even some disc brake cars received them.

JamesC

Thanks for the reply. Im thinking about buying some aluminum drums. Less rotating mass.

Aluminum drums warp very easily. I work for a Chevy dealership and we have to replace probably half of the Aluminum drum hats that come in for a brake job simply because they are too out of round. They don't stand up very well to aggressive driving.

ok thanks, ill save my money for a rear end swap! Get rid of these 3.08 to a 3.42!