Actually it was not the pace car driver Eldon Palmer of Palmer Dodge that caused the wreck - It was the track people who caused it.
During the weeks before the race he had been practicing with a disc brake equipped car. He knew exactly where to start braking by the placement of specific braking marker cones/flags on pit road.
On the day of the race, the track people replaced his disc brake car with a four wheel drum brake equipped car. To make matters worse, the braking marker cones/flags were removed after the race started.
He came down pit road hard and fast, noticed too late that there were no cones, started braking, and if you have ever driven a Chrysler with 4 wheel drums you know what happened next...the brakes faded out to nothing. He actually had a clear shot to roll out onto the apron at the end of pit road but the track officials stood in the pit lane exit giving him the choice of killing them or going under a grandstand.
You can actually see in the film footage the track people standing in the exit lane, directing him right into the media stand.
https://www.youtube.com/watch?v=OTNDPmIO4Lw
The actual pace car was not very heavily damaged. It had some fender and hood damage and was purchased a few years back from Mr. Palmer by a collector.