Today, dollar for dollar, is the 318 faster than the 340 ???

Converter and gear will always cover up a lack of bottom end torque. Unfortunately, that works much better in a purposed race car. Not so much for daily's that leave the county a lot.
Agree, that's where a 440 or stroker comes in. lol
There comes a point when anything under 383 cubes will be hampered by no low RPM torque as the HP goes up.