A white 1968 Camaro RS/SS convertible was used as the pace car for the Fireball 300 NASCAR Grand National event held at the Asheville-Weaverville Speedway in Weaverville, North Carolina on Sunday, May 5, 1968. This track was a small 0.5 paved oval and David Pearson won the race in his 1968 Holman-Moody Ford Torino.
I found this picture at Getty Images. The caption states: "Weaverville, NC - May 5, 1968: David Pearson (No.17) and Richard Petty (No. 43) bring the field down for the start of the Fireball 300 NASCAR Cup race at Asheville-Weaverville Speeadway. Pearson went on to score the win."
See it here: https://www.gettyimages.com/detail/news-photo/david-pearson-and-richard-petty-bring-the-field-down-for-news-photo/107648961
This is the only image I can find of the Camaro pace car for this event. I couldn't even find an image of the program cover.