There is a preview of the book, 'Shelby Cobra Fifty Years' on Google - a must for any Cobra fans:
Shelby Cobra Fifty Years - Colin Comer - Google Books
One notable and surprising inaccuracy on page 22 under the picture of an AC Ace where Mr Comer comments: 'One can easily see the amount of front-end restyling Shelby performed to turn the Ace into the Cobra'
The fact is that AC had already modified the front end of the Ace in the final Ford engined version, the Ace 2.6 which was first built by AC in 1961; 37 2.6s were produced by AC. Shelby cannot therefore be credited with the shape of the early Cobra - AC had already done the work. See pages 26 and 27 of Trevor Legate's 'Cobra, the First 40 Years' book and the attachments below.
An original ('60s) Cobra weekend held in Germany in July included an AC Ace 2.6 - the engine noise is the givaway!!
acceleration test with a great bunch of Cobras - YouTube
Shelby should receive all the accolades for the work he did on the Cobra, but so should AC Cars for their contibution.