Von, be very careful on buying a used set of ported 906 to M.W. intake port size. It is very easy to mess those heads up trying to make them better,(to many valve jobs, cut in the wrong places and so on ) if you really want them take them to a reputable machine shop with a good flow bench and have them tested, post the results on here before buying them to see what the knowleagable head guys on here think of those flow #s first before buying for the heads