David, street Cobras didn't have hood scoops; you probably already knew that. However, street Cobra owners were known to install hood scoops, roll bars, side pipes, etc. to get the "look" they were after...and the hood scoops did come riveted on from the factory. When I built mine, I too wanted a street car, but I wanted it with side pipes, roll bar and the hood scoop...and it took me a while to accept the fact that, to be as original a period piece as possible, I'd have to accept the riveted on hood scoop. It's what they call building the car as original, "warts and all".
On the other hand, it's your car, build it your way. (Yes, that was intentionally inserted to confuse you.)
Sidewinder intakes came on side oilers (medium risers). I don't know if any 428s came with a single four on Cobras, surely Shelby would have installed one if that's what you wanted; a low riser intake would have been period correct on a 428, and the sidewinder and PI intakes have the same casting date of '66. CJ intakes have a '68 casting date. While we're talking Medium and Low risers, let's clarify that, while the ports were different between the two, the carb height is also higher on Medium risers. A Medium riser intake will fit on low riser heads, with a
possible port mismatch.
Dan