Would like to know what changed on the early frosted and chrome covers. Assume the spinner can be changed but not sure the cover itself changed. Any dimensions on differences and pictures is appreciated.

 

Welcome to the forum.

The best advice I can offer would be to see if you can get your hands on an NCRS judging manual.

 

Agreed, the manual is a great source but more details on "thin radius" was not clear. I believe it is the distance between the hub diameter and sleeve portion that goes into the steel wheel. Like to know the difference in distance measurement.

 

Besides possibly talking to an NCRS judge, maybe checking with some of the Corvette aftermarket suppliers could answer that question.