To make a hood scoop at least minimally "functional," you typically need to drill a series of holes under the scoop, so that cool air that the scoop traps gets pulled into the engine bay to cool the engine and get cooler air into the intake. The cooler the air, the better and more powerfully the engine will perform. But even better than this crude method (the results of which are highly questionable anyway) is to find an aftermarket hood with a built-in scoop. Some of these feature something called "ram air," which basically takes in air through the scoop and funnels it through a tunnel to come out directly over the air intake. Some people still think this is still questionably "functional," but you have to think that, to the extent these things help by bringing cooler air into the engine, the versions that direct the air to the exact right place have to work better, right?

The Proglass Mystery 7 Hood
The hood you are looking at above is 1 of only 2 that were ever made. There is a reason for this.
For a short while, there was a company making aftermarket mustang parts called Fang Performance. One thing they made was a hood they called the "Mystery 7," which was based on the style of the 1967 Shelby GT hoods.
As the Fang Performance guys began to design this hood, there was a division among some of the decision-makers and craftsmen. One guy wanted to make the hood with "notches" that were typical of the 1967 Shelby hoods. Some of the other guys thought that, even though this would more closely mimic the style of the 1967s, it simply didn't go well with the lines of the 2005+ Mustang (btw, this body style is called the "S197," so now you'll know that if I ever say that - easier to say than 2005+, or 2005-2009 Mustangs or whatever). Well, the pro-notch guy was the one in charge, and his opinion eventually prevailed, and Fang started making these hoods with the notches. They didn't sell very well, and Fang eventually went out of business, selling a lot of the mouldings for their parts to a new company called Aeroform.
Here is a series of pictures that demonstrates the issue well (pulled from the thread I linked to above):
2. This is the Fang hood with the notches:
3. Here's a photoshop of what Fang should have done instead:

Well, one of Fang's fiberglass workers, who's very well known for his fiberglass skills, a guy in Indianapolis named Terry DeLong, left Fang and struck out on his own (either forming, or working for an outfit called Proglass, I'm not exactly sure). I guess he felt passionate about the notchless hood, because he created a moulding for one, and ultimately fabricated two hoods, giving them (from what I understand, at a very fair/low price) to two guys he knew, Chris (the sonic blue mustang above), and another guy, Tom. Soon after that, Terry began doing other things with his life, took up other interests, and stopped working with fiberglass. So long story short, only 2 of these notchless hoods were ever made.
When I came across Chris' posting, I thought, "I have to have that hood!" But given Chris' story and the fact that only 2 were ever made, I pretty much knew I was out of luck. Nevertheless, I wanted to do more research, so I googled "Proglass Mystery 7 hood," and found some other postings Chris had made on other websites. In one, I saw that he mentioned the 2nd hood was for sale (!!). However, I was looking at the end of November, 2008, and Chris' post had been from the previous August, so what were the chances it was still available?
Well, I send Chris a personal message over that mustang forum, and he told me he wasn't sure what the current status was, but suggested I contact Terry. He had posted some contact info for Terry, but I had tried it and found the numbers disconnected, and he had since left Proglass. After a little while of some deep searching, I found an email address for a Terry DeLong outside of Indianapolis that tracked to a machine shop. Hoping this was him, I shot him an email, and soon heard back from him, saying that the hood was, indeed, still for sale, and that a buddy of his, Tom, currently had the hood.

The second picture, btw, shows the functional "ram air" - it may be a little hard to make out, but there is actually a tunnel from the open "nostrils" of the scoop over to that cut-out square on the right, which, when the hood is closed, goes right over the air intake.

So Terry said he would contact Tom, ask what he wanted for the hood, and help out shipping it. He did that, came back to me shortly with a very fair price (several hundred dollars below typical aftermarket hoods), and I accepted. Shortly after that, I spoke with Tom on the phone, got information on how to paypal him, and did so. I'm currently waiting for the hood to be shipped.

Because the hood extends, there are some additional pieces that go with the hood to make the exension look right, which you may have noticed, for instance over the headlight in the above picture (I call this the "eyebrow"). Here are some close-up pictures of those extensions. 
From what I've heard from Chris, and from Terry himself, the fit and finish on this hood is impeccable, A+. This is important because aftermarket fiberglass hoods often need a lot of work to get them fit appropriately on a car. Without that work, they can be warped, leave large gaps, etc. Not good. So the fact that this hood was hand-made by a fiberglass craftsman who really knows his stuff, and has already been successfully installed on a Mustang, is all good news for me.

This is particularly key because there have been a few guys who have installed the notched Fang version on their cars and found the work to be very substandard.
What This Has To Do With The Price of Tea in China
So what's the point of this story? Well, having come upon this great hood, styled after the 1967 Shelby GTs, it got me thinking about doing a full tribute project, whereby I would transform my car to look as much like a 1967 Shelby G.T. 350 as possible. These S197s were styled after the Mustangs of the 60s and 70s, and just beg for retro-styled mods. So deciding on this hood was the genesis of my tribute project idea.
This post is long enough, believe me, I know, so I'll forego the details now. In my next post, I'll tell you a little more about the '67 Shelbys, show you some cool pictures, and tell you all the elements that I plan to mimic in my tribute project.