From what I see air flow adds more torque engines making 1.2 - 1.5 to 1 lbs-ft per cubic inch have serious carb head cam combo. Not saying you should throw on big port heads cause while it could make more torque per cubic it will be at an rpm not so street friendly unless we're talking big cube engines. Smaller cam carb head combo will aid lower rpm torque but 318 over 360 would probably slightly advantageous to the very low end but a cost to low mid to high. I think everyone got everybody too afraid of air flow yes you don't want hogged out W2 on a mild 318 daily driver but I'd rather make power from heads than cam on a street engine like the new LS and Hemi engines.