Just went throu some magazines... wow, just found an article about tuning the valver engine...
You can download the article from here:
http://perception.no.sapo.pt/maga/article.ziphttp://perception.no.sapo.pt/maga/article.zip
http://perception.no.sapo.pt/maga/article2.ziphttp://perception.no.sapo.pt/maga/article2.zip
Nice!