On the W-2s.. you can get over 300.. on mine the one set is 302.. the set on my 416 flow 310.. I did have to tube one intake port where I cut through but they are on the car now... I have heard of some W-2s going as high as 320.. but I dont know that for fact but mine were flowed on 2 benches.. the one at Chrysler and another local to me.. they were within 3 cfm .. but if I were to port another set I wouldnt go that far.. the issue is core shift