Here is an excerpt from that Automotive Industries article.
"these are within 2% of each other in power output--that's excellent," he says. Airflow through the heads is "significantly boosted," Dempster says. According to Rhoades, each honed intake runner shows a 2 cubic feet per minute (cfm) improvement."
That's a 24cfm improvement in airflow over a stock UIM or right about that 180cfm rating.
