The device in the photo is an Allison V12 jet engine starter that was adapted to power an electrical generator.
The two reels mounted alongside it held 1/4 mile of electrical wire cable which was laid out on a drag strip to provide voltage via a electrical pickup to an electric motor powered 4 wheel drive modified Austin 1100.
It was called "Super Slot Car" and was built and operated by a gentleman called EJ Potter, AKA "The Michigan Madman" in the mid '60's.
Heres a photo of the car the device powered.