Big Block Cylinder Heads "915 vs 906"

I'm just following up on an old 1970 Mopar article,

With respect to the #915 and #906 Cylinder Heads.

On a 1970 'stock' 440 GTX with 3.55 Gears and Automatic.

A 'brand' new GTX with nothing more than a 'general' quick performance tune-up,
ran the 'Quarter-Mile' at Milan Dragstrip at 14.11 @ 99.19 MPH.

The #906 Cylinder Heads were pulled off and CC'd at 88.2.

Swap the #906 heads for a set of Stock #915 Heads {w/Factory CC level at 78.8}

Result............ 13.78 @ 102.34 MPH

Gain............... {-.33 ET} and {+3.15 MPH}