Heyworth & Normal are about 45 minutes down Interstate 74 from where I live. I drive through there all the time, however, I didn't grow up here. However, I have a good friend who grew up and still lives in Heyworth. He and/or his Dad (& family) may know of that car and remember it. Heyworth is not that big...
I'll forward your description on to him and ask... maybe something will turn up. Anything else you can describe??
Ken