if it was excessive blow by he would have seen it in his compression numbers and leak down numbers also. due to the fact that he stated the head has been used for years i would look more towards the seals that have never been touched.

Quote Originally Posted by Tech5 View Post
Explain your theory on this one please?

His isn't smoking at idle nor low rpms ,nor at first start up. So valve stem seals will continue to leak not only at high rpms ... When he is at high rpms and then it starts to smoke that is when he is at MAX pressure causing blow by from the rings .