Flow tests of AFR's 325cc big-block head are among the best of a series of heads tested. Good flow figures, a moderate port volume, and good swirl promised to deliver the results we were looking for on the dyno. Here are the flow figures produced by our test heads. Note that the curve substantially levels out by the time .700-inch lift is reached. This should work well with a valvetrain lifting to a little over .650 inch.