I know its not the greatest picture but I found an image that possibly demonstrates that a white 1969 Camaro of some sort was used as the pace car for the USAC Champ Car Indy 200 held at Indianapolis Raceway Park in Clermont, Indiana on Sunday, July 27, 1969. The event consisted of two 100 mile heats on the 2.5 mile road course portion of the facility. Dan Gurney won Heat #1 in his Eagle Ford and Peter Revson won Heat #2 in his Brabham Repco.
If you look at the very right side of the picture you can see the rear portion of a white pace car. To me the squared off wheel well, the bumper position, the rear spoiler and what appears to be a Rally Wheel makes me think that it is the back end of a 1969 Camaro. Since this track was owned by the same owners as the Indianapolis Motor Speedway at the time, it makes sense that this could be a 1969 Camaro RS/SS Z11 convertible being used as the pace car. It might even be one of the actual pace cars that was used to pace the 1969 Indianapolis 500.
This is the only image showing the pace car for this event that I could find. Hopefully another one emerges to confirm or disprove.
Click on the following link to use the magnification tools for this image here:
https://library.revsinstitute.org/digital/custom/single-image?id=205054&collection=p17257coll1
