I ran across this article while searching some open-wheel racing history. It's dated 1996, around the time that Mopar decided to get back into short track open wheel racing in the US big time. I'm better informed about WOO than I am about Silver Crown, but I believe that Silver Crown was (is?) the biggest motored sprint car series that did not have wings.
http://www.theautochannel.com/news/date/19960701/news01115.html
More on Sills and the Silver Crown series. This is from Mopar's own "Milstones" site. Shows how you can market "Performance" when you support US racing series.
Mopar Milestones - 60 Years of Mopar!
1937-1997 1996
1996 Team owner Gary Stanton and driver Jimmy Sills give Chrysler its first USAC Silver Crown championship with a season-ending win at Del Mar; Mopar chalks up a record $3 billion in sales.
http://www.theautochannel.com/news/date/19960701/news01115.html
More on Sills and the Silver Crown series. This is from Mopar's own "Milstones" site. Shows how you can market "Performance" when you support US racing series.
Mopar Milestones - 60 Years of Mopar!

1996 Team owner Gary Stanton and driver Jimmy Sills give Chrysler its first USAC Silver Crown championship with a season-ending win at Del Mar; Mopar chalks up a record $3 billion in sales.