Locobuster1

After searching around I found the movie! It was titled "Death Race" and came out in 1973. It stars Lloyd Bridges, Roy Thinnes and Doug McClure. I was right it is a P-40. http://www.imdb.com/title/tt0069953/

I have also wondered for a long time what the name of this movie was, I saw it many years ago. If I am not mistaken the plane is a P-40 Warhawk. It's in color, I would say 1960's vintage.