This question should likely be posed to John Mummert..however I realize he is a very busy man & now sells new aluminum cylinder heads, & no longer offers head porting, so I'll try it here. Maybe someone who is well familiar with head porting can clearify it for me?. Quite some time ago, I obtained a copy of his published instructions in YBM on porting factory heads.. (sorry I don't currently have the issue #)  Problem is, that there is one area that I just can't get straight in my head, no matter how many times I read it!  On the 4th page of the instructions, a paragraph starts; "The vast majority of flow in both ports..... travels straight towards the head bolt (boss). Next sentence says  " The best treatment of this boss is to grind an angled face to direct flow past it. (to the right) This is more important than trying to blend the boss into the right hand wall of the port up stream from the boss." Un quote.  Did he mean the right hand wall, looking from the valve end?   Further he stated; "remember there is practically zero flow on the right side of the upper port to within 1" of the head bolt. (boss).  "Leaving a slight lip of about 3/32" where the right hand port wall meets the new angled surface of the head bolt boss, does not hurt flow." Unquote.  Does he mean across from it, on the right wall looking from the top end? (it doesn't seem likely but ?)  Or looking from the valve end up the right wall? I've read this section a number of times & just can't get it sorted out... ( I should mention that the copies I have are not that clear in spots & with the scanner I have, which isn't very compatible with our computer & copier, it's not practicle for me to make additional copies for others, sorry)  Any informed advice appreciated. I don't want to mess up the spare set of "G" heads I have here. - Thanks.           


Paul