[CoBro]

There is no right or wrong answer to the question really! Thanks for the history lessons of all the American motorsport innovators, and they should be recognized. Please post more about these men and their accomplishments if you can.

*Shelby whooped Ferrari's butt in their own back yard. That's good enough for me.
*Mickey triumphed in road racing, Indy, Bonneville and my personal favorite, off-road racing. Didn't he campaign a Bronco?
*Garlits changed an entire motorsport segment and saved a lot of lives with the rear engined dragster. All the aero innovations he devised are still evident today.
*Special mention to drag race legend Shirley "Boom Boom" Muldowney who inspired many female drivers of all disciplines, and broke the stereotype that women can't or shouldn't go fast.

If I had to make a choice I'd have to say Mickey Thompson.
The sheer number of different types of motorsport he competed in and innovated is astounding. He had the career of 4 or 5 people combined!