Waayyyy back when I used to run miles for time my best was a 5:07. Now, I have no idea but I'd venture to say it's over 8 minutes. 200+ pound non-runners, don't keep good mile times.
I've found running to be an odd measure of conditioning though as a bit of sport specificity seems to come into play. I've found that you can have good conditioning, but if you don't run, your mile time can be truly poor.