I'll take a stab. First, the standard hood on a Challenger has the two simulated air intakes much to close to the surface of the hood to be of any use for air intake. Teh main source of air would be at the front of the grill the recessed grill, though sexy as hell on the Challenger, isn't the most aerodynamic. There is a large build up of pressure at speeds. Some of this is good for cooling as the higher pressure will push air through the radiator.
With that said, it is doubtful that is the source of the issue. I am guessing that that you are missing or have ill adjusted hood bumpers. There are multiple fixed rubber bumpers at the rear of the hood. If the hinges are adjusted properly, the rear of the hood should rest on them. There are side bumpers that have spring loaded tapered rests that should keep hood from moving side to side and support the center. At the front are two adjustable bumpers that can be raised and lowered to adjust the height of the hood at the front. The latch should be adjusted to pull the hood slightly against the rubber stops on these adjusters while the height of the adjusters keeps hood aligned with fenders.
I'd check these adjusters and bumpers first.
I checked all that and it looks good. I even took a few photos showing pretty tight lines when the hood is closed (no misalignment and such). But I did take a closer look at the front grille and can see that the air that passes through either hits the radiator or probably goes straight up against the front of the hood. And the front of the hood is where the movement is.
Is this just a normal thing for older Challengers? Maybe blocking off the space to the left and right of the hood latch base would help?
