It is the Woodill Wildfire XK120 named The Idaho Special. and as HEMI426 said this car was used in the 1954 movie Johnny Dark starring Tony Curtis and Piper Laurie and I have read that was filmed in Written in the Wind too.
This is a brief story from auto restoration 101
The car was created by B. Robert (Woody) Woodill. His dad owned a car dealership in Downey, California. Woody bought his fathers share in 1948 which made him the youngest Chrysler dealer in the country at that time. Woody was wanting a sports car and was thinking about buying a Jaguar but everyone talked him out of it because they were hard to work on.
There was a Willys assembly plant nearby and Woody had access to it so he decided to use their parts along with a Glasspar fiberglass body to build his own sports car. He did some modifications to the bodies such as raise the hood and deck, added a hood scoop and extended the quarter panels to accept the Willys tail lights.