Dave Friedman wrote a great book about early the early '62-'65 Cobras called,
"Shelby Cobra, the Shelby American original archives 1962-1965. I tells about early 260, 289, and FIA Cobras with alot of good racing photos. It also mentions something about a dubious experiment to put a 427 in a Cobra, but I think that experiment was not very successful for racing cars, more for looks and bragging rights
...
I got a copy from Barnes and Noble, but had to order it.