I know the car on the left is a 1907-08 Ford Model K Roadster. If the other two are a White and Buick, I think I know what race the photo was taken at.
Any thoughts on what the other two makes are?
I'm doubtful that either one is a White or a Buick, but I can pretty certainly say that neither is a White. Wrong hood shape and you can see the front axle too easily.
The center car is not a Buick. The car on the right, going by the front fenders, might be a Oldsmobile or a Mitchell
The car on the right is a 1907 - 8 Olds Flying Roadster i believe.