The Everett Morrison I used to have was built as a track car with a chin spoiler. I've had it up to 140 at the track and it was rock solid. It's purpose is to prevent air from getting beneath the nose.
EDIT: I can't find a good photo, but it was about two inches tall and attached to the bodywork below the
oil cooler opening. It went down and not straight forward as on some larger spoilers.