I agree with Kevin...
Typical for aftermarket wheels, they say "ZR-1" wheels and will never fit right.
If the fronts are 9' and not 9.5, they are off too.
It's worth it to look for "OEM" ZR-1 wheels for weight savings and original appearance.
I appologize and not trying to ruin your purchase, but only explain the truth about aftermarket wheels. (we should add this to solutions if it isn't already there!)
David