Your questions are not "stupid" - you have picked three very unique cars that might certainly give you the impression that's there's something different about them.
The first picture is, I believe, a very nicely done Hi-Tech replica of CSX3002. The second picture looks to me to be the real CSX3002. The first few early comp big block cobras had a few 289 Cobra attributes - like the nose and the dashboard. So the more pointed 289 snout, plus the racing windscreen, AND the angle of the photos, may make those cars look longer.
The third car is, like Kevin said, CSX2196 - the "Flip-Top". A one-off body that seemed to be sectioned down the sides, making a much lower profile shape than any standard Cobra body style.
Welcome to the forum.
Jeff
