Shallower base/drop plate?
So its safe to say you are using a 14 inch diameter air cleaner. Go to your local parts house that stocks K&N. If you are "just barely" having clearance problems they make a 2-1/2 inch high 14 inch diameter filter (will fit into your base and cover). They also make a 2 inch high but thats a little restrictive I think. Might want to look at a smaller diameter also. You are probably getting interference on the inner structure that goes across the back of the hood. A smaller diameter unit would fix the problem.