07/11/2023 – The last year all four GM manufacturers officially participated simultaneously. Interesting that the Oldsmobile and Buick carry OEM identification while the Pontiac and Chevrolet are identified by their model name.
![](https://pontiacracing.wordpress.com/wp-content/uploads/2023/07/1991gmnascarmanufacturers.jpg?w=833)
07/11/2023 – The last year all four GM manufacturers officially participated simultaneously. Interesting that the Oldsmobile and Buick carry OEM identification while the Pontiac and Chevrolet are identified by their model name.