Perhaps the high interest in muscle cars is waning and people are wanting something simpler and cheaper. I have 2 muscle cars of my own, but it seems I get in the panel far more often than the Chevelle or Beaumont, both big block cars. I also have observed more of the younger generation getting involved, often purchasing a truck rather than a car. As to whether or not 60-66 trucks are more popular then other truck series, I have yet to see that here, but I certainly like them.
