If you keep the air box, then seal it all in, that would make the ram sit off to the side a little bit, I think that would look pretty sweet, there is a guy around here that put a newer model mustang scoop on his Panel LT(functioning btw)

 

Here's a link to pictures of my Corvette with a cold air shaker hood scoop.If you look on page 13 of the pictures it shows how I put it together.

http://s35.photobucket.com/albums/d160/62f79/Corvette/

 

Just so you know, a hood scoop is a cosmetic mod. Best case scenario is it's a decent cold air inlet. There's no such thing as "ram air" at velocities meaningfully below the speed of sound. Despite Detroit selling the concept for decades, this is a situation where the reality of the fluid dynamics is at odds with our intuitive grasp of it.

 

Hence, why a thin strip of flared plastic on the leading hood edge alleviates bugs from our winshield(and paint) or we never saw a newer working version of the cowl induction from a 70 Chevelle SS.
But one could dream............

 

Could you make the argument that any gain from the better cold air inlet is offest by the reduced aerodynamics of the vehicle???

 

Forward facing scoops have a trade-off. They don't overcome their inherent drag until after a certain speed is reach (varies with car and scoop design). They do their best at high vehicle and engine speed when the engine can use every bit of air you can feed it. Rear facing scoops (i.e. cowl induction) only work well when certain parameters are met. They use the low pressure area at the base of the windshield and the vacuum created by air being pulled into the engine to create an increase in air flow into the fuel system. If the scoop isn't sealed to the fuel system inlet, it does nothing but look pretty.

Most scoops of the bolt on variety look tacky IMO. They look like something from Whitney or Warshawski (sp?).

Do what the Dodge Boys did back in the '60's, take out two of your headlights and use the openings to feed air to the engine (won't work on an HHR) but you could feed air from the lower grill opening. I know it don't look as neat, but if it works who cares.

 

I personally really like this SS

 

This is a scoop i found in a bargin bin at a giant auto, I had to cut out the holes, and then i made the custom grills, i think it fits the hhr's body style pretty good.

 

I converted my stingray to use the earlier years L88 cold air induction.

 

Functionality...I had a '73 comet w/302 that I had installed a early style mopar hood scoop(aftermarket) Inside was a moroso velocity stack with a filter mounted on top.The hole in the hood was no more then 1/2 in larger then the filter dia.,the entire filter protruded above the hood with the base at hood level opening.How well did it work? I had to watch weather as if the humidity was high and the weather a bit cool below 50f) I had to close off the opening because the air would ice the throttle base and lock the throttle and try to close the choke.Yes the exhaust xover was working.It was very efficient..though it was not planned to be..was just meant to be "pretty".
Having several scooped vehicles over the years, this was the only one that did this.