Photo: powercars
Watch this original footage shot at the event back in 1960. If you notice even though the car produces incredible amounts of power, it still requires a little nudge by the support car to get it moving. The reason for that is the gearing is set so high for top speed rather than acceleration. Think of it as trying to start on the hardest gear on your mountain bike, same idea.
This is the full 12 minute video done at the event that explains things in more detail.