That is the Morgensen Special.
It was built with a flathead straight 6 Plymouth engine, which was replaced with a Buick Nailhead after a year or so.
The car was involved in a deadly crash at Torrey Pines, and after that it went to Max Balchowsky.
Max and Eric Hauser raced the car, it was repainted in yellow, and got the nickname Old Yeller.