Does an increase in airflow (intake or exhaust runner) move peak torque up or down the RPM band?

Another way to look at it. Take the somewhat useless formula that people use for carbs.
CID x RPM/ 3456 = CFM

Take A 273 @ 6500 rpm or 318 @ 5580 rpm both would move a theoretical 514 cfm. To fed those engines at those rpm your gonna need enough air flow to support them. Though a combination of mainly cam and heads. There’s many ways to get there less head more cam or more cam and less head or in between. No matter which way you go should have a similar powerband but more head and less cam should be the most streetable.

P.S. that’s why the formula doesn’t work for picking a carb because even though we know we need 514 cfm it doesn’t help with which head we need even though we know the head cfm.