I've never heard of the '79 Camaro Z28 IROC Sprite pace cars until now. Only 25 were made for pacing the IROC races

Chevrolet reportedly built 25 pace cars for IROC duty, and these were retained by GM and cycled from track to track for service between events. These so-called “Sprite cars” are instantly recognizable thanks to their white paint over rare green interiors, a combo essentially limited to the pace-car run.

https://www.hotcars.com/dennis-collins-sale-rare-camaro-sprite-z28/