Guess I missed the part about the Comet...I used to autocross and open track my '65 Caliente before I bought my first GT350 (many moons ago).
I am not aware of any insurance company that will cover you for ANY kind of track event. Most policies these days even specifically exclude "driving schools", or any kind of track use. I believe driving the car on the track these days is pretty much at your own risk.
Jeff