Good Question,
Here is an article from 1966 that compares the street roadster to the S/C race version, there is one picture of the engine bays that may give you an indication.
Sports Car Graphic, November 1965, Double Cobra test
You may see some other areas where the two differ.
Look at this original street car for some additional views, it look like a remote filter but, it may not have been there by Shelby when it was first built.
1966 Used Shelby Cobra 427 at Canepa Design Serving Scotts Valley, IID 6863033
TR