Airflow to Cubic Inches

I’m still going with;
That formula does not apply for the typical hot street/bracket race build.
(Especially those where the build doesn’t involve “going where no one has gone before”)
In those situations (imo), you’re better off using a similar build with known results as the basis for your plan, and tweak as necessary.

As for the OP’s desire to build a 650hp 493………you def don’t need any formulas for that.