920 vs. 302 Heads

Here's a comparison between the #675's and the #920's from 69 cuda 440

General Overview,

The #920 Cylinder Head gives you about 2% more Power {5 Horsepower} over the
#675 Cylinder Head.

When using the 'Stock Engine Components', and relative minimum Factory CC Specifications
for each Cylinder Head {#920 = 57.3 CC.s} and {#675 = 60.6 CC's}.

With the 'stock' Commando Camshaft {.425" Lift ~ 248* Duration ~ 26* Overlap},
shrouding of the Valves is not an issue in the #920 Head.

Compression defeats Flow

#920 Cylinder Head 'Compression'... {+ .35 Higher Compression} = 2% Power Gain = 5 Horsepower
#675 Cylinder Head 'Flow'...............{+ 4%}
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Next Test,

To take the #675 Cylinder Heads and mill them an additional .021" to bring the CC Level
down to 57.3 CC's {Equal to the #920 Heads}.

Then test the 273 with the #675 Heads, with an 'equal' Compression-Ratio to the #920 Heads.