I've seen A LOT of posts about making HP with a 318-So why is it so ???

Not even looking at the values........ the two results show a 2000rpm discrepancy in where the tq peak occurs.

The real world result on the TQ increase for this build was......just about 2% based off the factory gross rating of 360ft/lbs.
The bigger heads and cam, 4bbl carb and headers moved the tq peak up 2100rpm(2400 up to 4500), and that results in the gain of 76hp.

Wanna try a 440 6bbl?