Ram air might work on a diesel truck or a muscle car but there is one problem that I see with this idea. The radiator will block off a lot of the airflow. And what does get through will be warmer, less dense air. That is bad for hp. Plus the length of the tubing in the frame & all the bends would hurt power that much more. The tried & proven intakes & filters that some of us run seem to be the best bet.

However if you still like the ram air idea, try to fab up something like what the Harley drag guys are using. It works for them so you might try to experiment with it.