E-street vs Promaxx vs 440 Source

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.....