It’s really quite obvious.......
The better the heads are, the more “off” the rest of the combo can be and still reach the goal.
On a 13:1 blueprinted short block with a really good cam and induction/exhaust, properly set up unmodified heads would get you there.
As the combo gets “worse”(smaller cam, less CR, etc), the heads need to be better.
Here’s a really mild one using a pretty short duration cam....... but really good heads:
440-Cubic-Inch Big-Block Pump-Gas Mopar Wedge Makes Over 500 HP and a Whole Lot of Torque.
The other end of the spectrum:
Another very mild 440 build.....