The body shell looks like a badly done McLaren M8A Can Am car from the 1968 season. I don't think that is a Cox product since they had a sponsorship and product tie-in with Chapparal Cars and AAR Eagle and did much more accurate work on tether cars of racers built by those teams..

[link=http://www.bruce-mclaren.com/images/elkhart_lake1.jpg]McLaren M8A[/link]