The chart in the book answers the question for most guys. If they are shooting for more than 1.5 hp/cubic inch then they'll need to get more sophisticated tools. Airflow measurements, velocity measurements, swirl, tumble, etc. would all be helpful for higher power combos.

The book is $20 and answers most bracket racer questions. PipeMax is $50 and handles most race engine builder questions. After that the money gets more serious.

I've built 900 hp big blocks with not much more than PipeMax and a credit card. You have to assume that the head porter knew his stuff when you buy an off the shelf ported head but that is just the way it is. Not very many guys have the money to buy heads which are flowed, mapped, fixed, etc.