Research is the key! I have taken my daily driver inlets out to 31mm removed the valve guides for the work and shaped them as per what I read up. The exhaust ports were opened but kept the same shape, which is vital on the cVH (D Shape). The maniflolds were port matched. I am not saying that cosworth have been on the phone for advice or anything but it has made a noticable improvement in both power and response! It has not been on the rollers so I cant quote figures.

For what it cost me do do I was made up but as for it being the pinical of CVH head flowing I very much doubt it. It depends what you want.