they are mostly decorative.I have a friend that grinded the outside fins on his v8 valve covers and then polished them and the looked like crap with dips and what not.He had to get another set of valve covers and have them machined off and slowly sand them until it looked right and had the right contour.He had to remove one fin due to generator clearence problems and removed the other three to match and says he had atleast 30 hrs into them.

Why not just polish or paint in between the fins?

Or you can find another intake that does not have any fins.

Gangster whites and straight pipes.....