Why are 318's low HP and torque?

YY1 said

I'd be interested to see a 318 built as close as possible to one of the 4 barrel 327 specs...and see if that 9 inch displacement advantage made that much of a difference.

Click to expand...

You would need 10.0-1 Compression-Ratio Pistons, a 4-Barrel
Medium-Riser Dual-Plane Intake and a Carter AVS {625 CFM}.

And an improved Exhaust Pipe System.

Not sure if that gets you to 250+ Horsepower.