Anyone who has an interest in why cylinder heads perform and what sort of myths are out there- look at this site- while it doesnt deal directly with Porsches it is one of the best sources I have ever found on explaining what helps cylinder heads and what hurts- i am sure you will find it interesting reading- check through the whole site- it is fascinating
<a href="http://www.theoldone.com/components/cylinderheads/" target="_blank">http://www.theoldone.com/components/cylinderheads/</a>
<a href="http://www.theoldone.com/" target="_blank">http://www.theoldone.com/</a>