Dirt track vent..

Simple , they have joined the nhra and nascar , "chevies only "!

It's been that way forever though, it just continues to get worse. Both Wally Parks and Bill France had hard ons for Chevy so much that they had their hands on the scale. Were it not for them, Chevy wouldda never had a chance between Ford and Chrysler. No way, no how. They had to sanction everybody else and even then Chevy almost couldn't win.