Sources for the Cobra research are many and varied. Hopefully, one of these will help you find the detail you are seeking:
CobraCars.be Although the original site is Belgium, Google can translate any pages as required.
CSX3282 Brooke Clarke’s 427 Cobra
A list of books from the library of Art Gumbus. Pretty good list but doesn’t include books since 2007 Cobra Books
Years ago, the Kirkham site included an excellent article of the subtle things of an authentic Cobra. Internet websites have a tendency to go off-line or disappear and, to my thinking, this info is too valuable to lose. I have duplicated the info in PDF format A GUIDELINE TO BUILDING AN AUTHENTIC LOOKING COBRA REPLICA
ERA Documentation: one of the best sites for kit build information. Click on the vehicle of your choice to reveal all kinds of technical info, both on the ERA build and Cobras in general