We have looked at auto polo here before, when it was generally played with Model T Fords and done the old fashioned way. Be sure to watch this short clip from back in the day when this rough and tumble sport was played.
Two press photos from 1951 show a different version of the game wherein the car is what you used to hit or move the ball. It appears that the car choice again was the Ford as the two cars above appear to be mid to late 30’s Fords. One of the goals appears to be the bulls-eye in the background next to the fence.