A white 1968 Camaro RS/SS 396 convertible was used as the pace car for the Rebel 400 NASCAR Grand National event held at Darlington Raceway in Darlington, South Carolina on Saturday, May 11, 1968. David Pearson won the race in his 1968 Holman-Moody Ford Torino.
While it is too hard to tell definitively, it looks like it probably says "CAMARO" & "OFFICIAL PACE CAR" on the door and possibly "DARLINGTON RACEWAY" on the front fender. If it's like several of the other NASCAR Camaro pace cars then it might say "REBEL 400" and/or "MAY 11th" on the rear quarter panels.
I took pictures of the Camaro pace car while watching the television show Glory Road on NBC Sports Network. This show featured vintage footage of the race.
The first two pictures show the car sitting at the end of pit lane waiting to go into action during a caution period.
The last two pictures show the Camaro going back to it's end of pit lane position after the conclusion of a caution period. Notice that the drivers side brake light bulb seems to be not working. Perhaps it had its turn signal illuminated??