My drag car (Duster) has a lightweight pin-on and it's a bother. Needed to add a pin @ front center over 120 MPH, so I have 5 pins total, but the 6-pack scoop at least provides a handle of sorts. I added some 1/2 x 1/2 angle along the fender inner edges to support it and a length of rubber at the cowl to support it; otherwise it sags.
Street Duster has an AAR 'glass hood for hinges & latch, and has the factory-style reinforcements, and it's easier to live with.
Mine are a lot smaller than a '71 Charger's is; something that large in a pin-on would really be a bother, I would think.