Petty claimed the reason for the unusual innovation was because the dimpled vinyl roof was expected to help the blue number 43 move through the air with less resistance - like a golf ball.
The real reason for the vinyl top was they had acid dipped the body too much and it was so wavy they needed to do something.... kinda like the rear wings on the Superbirds. Everyone wanted to know what angle of attack it was set at so they were always moving it around when it was really the side struts that made the cars work...
