
This question came up watching the recent Sears Point race where Canadian Ron Fellows again came close to pulling off a win - victimized by a badly timed caution and pit stop. Unless I've missed someone obvious (which I have the nagging feeling is possible) there must be a pretty large number of consequtive American winners, so it seems like a Fellows or Fittipaldi pulling off a victory would be a reasonably significant milestone and story.
I've been following the sport just since the late 1970s, so any historical winners would be of interest as well....