I think without it this NOS car would have went around me. Its like a shot of juice at the end without a bottle. Even a /6 car would benefit on the highway. Nothing wrong with a little ram air.
To big of a scoop hurts the aerodynamics more than the gain of the ram air. One of the reasons why Hemi scoops don't work as well. They hold back the car back like a para-shoot. But they look cool as do the six pack style.
68 Hemi large opening, 69 six pack had a riser off the hood but still to big. 70 almost perfected on the T/A. The Air grabber had no effect until 100 and above. 71 Plumouth Pointed the air grabber to grab air off the bubble. looked cool but didn't work any better. 72 Dodge perfected the scoop but never sealed it to the carb. The direct connection Chassis manual addresses this style scoop as the best for forced air induction. That is why I put it on the Duster.