Highest flowing sbm heads?

Ok have a question
All this talk about absolutely highest flowing heads available (no matter what engine or brand)
I understand that improved flow and velocity will help any engine, all else being equal. But is it really mandatory to get that last 1/4 cfm of airflow possible Out Of ANY engine of a given size? Any cam? Any CR? Built for any purpose?
Does it make as much difference on say a 360 built for a tow rig as it does on a 360 in a dedicated 1/4 mile race car seeking to eke out that last 10th???