3.8 mph gain from no hood? Pics inside and input needed

There’s an old racers trick of adding spacers between the rear of the hood hinge and the hood to create a gap at the cowl. It gives the air being forced through the grille someplace to go and can be worth a tenth or two.
As far as filtering, I would be tempted to try one of these, if you have the scoop clearance.
[URL]https://www.summitracing.com/parts/knn-58-1200[/URL]
And combine it with one of these
K&N X-Stream Airflow Top Plates 66-0901
There’s a taller element height available, too. You could potentially get several different height 9 inch paper filters to see what works best with the X-Stream lid.
The optimal filter height should be a balance between the airflow through the top and airflow through the outer filter. You don’t want to restrict airflow, but you do you want enough air coming through the top to have enough velocity to help air from the other element “make the downward turn”.