Those aren't dents...they're "speed lumps". They work just like golf ball dimples to help reduce drag and increase wheel speed! Old street racing trick! Surprised you guys didn't recognize it. Like a log!
Darn! I had hoped that they were uncommon fuel injection caps. Anyone want to trade for ‘55 Chevy dog dish caps in driver condition?
Lazy bunch of hotrodders! Never thought I’d see the day that no one would enjoy the pride of a job well done after having worked out the dings from caps such as these and then run them on your car!
These were, as X-Cpe said above, the hubcap option for the "big brake" '58 to '62 Covettes, which had special vent, vanes and backing plates for the big brake option.