Flow numbers and max HP potential

Here’s one example.
This one only beat that formula by a few HP.
383 Mopar, 10.5CR, unported 906’s that flow 235, dual plane intake, flat tappet cam.
Made 504hp with oxygenated fuel and an electric water pump.
.26hp/cfm shows 488hp.

What could have been done to improve the power without changing the heads?
-add 3 points of compression
-modern gas ported ring pack
-vacuum pump
-dry sump
-Roller camshaft
-tunnel ram with dual carbs
-merge collectors
-q16 gas