That doesn't mean the head is big enough. The original architecture of that head was designed in the early 1960's, with mid 300 inch displacement in mind that spent most of its RPM below 3000.
When the W2 head was developed, a big displacement. Small block was 360 inches.
The head is small for 400 inches. It's small for 340 inches if you want to make power over 7k.