Radio reception question

Corvette distributor sheilding was installed because the Corvette body's firewall being fiberglass didn't isolate the radio from ignition noise, it had nothing to do with reception whatsoever.
The fiberglass body on the other hand DID reduce radio reception, so the GM engineers installed what is commonly called a "ground plate" UNDER the radio antenna mount on all mid-year & shark Vettes. It was mounted below the fiberglass quarter panel, and has a ground strap that connects the ground plate to the car's chassis.

George