No, I don't think you are missing anything. Although, most cars use an intake or snorkel for the air cleaner that is about the same size. During normal cruise speeds, I think the air intake is sufficient.
With the CI hood, when you go to WOT and both doors are open (the inner door is really the one that matters), some people even consider that to be restrictive, especially with a healthy 454+ engine. Disconnecting the solenoid for the inner door, or, simply omitting the inner door and its frame altogether would provide full time cooler air as well as much less restricted air to the air cleaner. I have considered removing the inner door on my CI hood several times, but decided against it each time.
The outer door is really more for looks or the "wow" factor than it is for functionality. If you look closely, you will see that the air at the base of the windshield has a straight shot to the inner door even if the outer door is fully closed (just like a NASCAR intake!!!!).

 

Thanks for the reply Tom. It would kill me to disconnect something that I have spent so much time restoring the parts so they function correctly. I wonder if there are other options that where we can have or cake and eat it too. My car is mostly original, but it's not a points car either. What do you think of this option?

-remove the existing snorkel, cut another hole in the air cleaner base on the right side to replicate the hole left by the snorkel, and rig up 2 fresh air intakes to the air cleaner base with one of those kits. This may clutter up the engine bay...

 

I removed the inner flapper so it's always breathing cold air. The outer flapper just looks cool.

LK

 

Yep, not only that but I then cut the snorkel off the repo air cleaner for a cleaner look under the hood. Filled in the hole where the snorkel was and all is well.:thumbsup:

 

I agree that most cars have a sealed up air cleaner and pull air through the snorkel. The part that bothers me is the factory single snorkel CI air cleaner necks down pretty small on the end. Even our old 4cyl Accord has a larger plenum.

 

i haven't understood the concept of only giving cold air under near open throttle, why not all the time? my chevelle is a '68 so i don't have it there, but i have a '71 442 with a ram air hood and it works the same as your chevelle, it's only opens under low vacuum. was this to keep water from entering? keep in mind, these cars when new were in most cases someone's only car and driven year around.

 

i haven't understood the concept of only giving cold air under near open throttle, why not all the time?

I suspect that it was an emission control tactic, like the hot air hoses on a lot of cars that ran from the exhaust manifolds to the air cleaner. Emissions tests don't involve WOT so the cold air isn't a problem under those conditions.

 

If you have a repopped air cleaner and don't mind modifying it, couldn't you just drill a few holes in the bottom of the air cleaner, say in the back so you cant see it but it would pull air from under the air cleaner? Jim

 

My air cleaner is an original GM, but not prestine. I wouldn't mind modifying it if it went to a good cause. The thing that I don't understand is that my books all show a hot air "stove" in the snorkel...mine doesn't have one, it's solid all the way.

If I was going to modify it, I would want to bring in cool air, and use the C.I to provide the extra "kick". Have you seen those Ram Air set-ups that they sell for older cars witht he dual snorkel air cleaners? Kind of like that, but just to the base of the air cleaner, and no "ram", just fresh air inlet tubes running to the core support or something. I don't know, just tossing around some things in my head. I don't want it to look too gaudy (sp?).

 

I think the hot air stove on the CI air cleaner was 72 ONLY.

 

If you are at part throttle, you have considerable vacuum in the intake manifold.
At the same time, you have virtually no vacuum in the air cleaner housing--and that's easily verified if you care--just push a long hose (connected to a vacuum gauge) deep into the snorkel so the hose end is up near the air filter, tape it down, and go for a drive. (It'd be better to be on the clean side of the air filter--provided you have an access point for checking the vacuum.) No vacuum in the air cleaner housing means the snorkel isn't restricting air flow.

I suspect the necked-down snorkel is NO restriction at part throttle--the throttle itself is MUCH more restrictive! By the time the throttle is open far enough for the snorkel to be a restriction--I bet the cold air ducting is open.

No gains to be had just by opening up the snorkel.