First thing about heads period is how well they flow. And on what cubic inch size engine there going to be on with the associated parts for your goal. And that goal is???
In layman’s terms, the head should have the ability to make 2hp per cfm or flow the head offers. This layman’s math is not a maximum output but what a well built engine and combination should do.
So! If your ported W2 heads flow 300 cfm, then getting 600hp from them is a real possibility. But only if you have the right parts supporting them in trying to reach that goal.
Yellowrose & mbaird hit the nail on the head with there reply.
What is your intended usage and goal?
