I guess we need to add "that" to the list of reasons. Your findings also put a red face on a lot of us, including me. On the other hand, all three of my current Mustangs have the open type chrome air cleaner so I don't have a snorkel, and when I do clean-up (a word used in lieu of "restore") one, I adjust the flap valve wide open eliminating the preheater. Hey, it's California where I am.
Jim