Check out this article on the 1968 Camaro SS 396 convertible pace car located inside of the souvenir program for this event. It mentions that "the Raceway recently took delivery of five spanking new Chevrolet Camaros..." It goes on to say that "the cars are all the same shade of Corvette Blue and they're all equipped the same; 396 cid porcupine mills, the Chevrolet hydro-type trans, handling kits and disc brakes."
Notice that the door decal/stickers differ in this picture from the ones that are on the car during the actual race weekend.
posted by Bruce Ward at the Remembering Riverside Facebook page