I am rebuilding a Buick 3.8L for my 91 Buick LeSabre. I went .030 over and I am working the heads. I had new guides installed, new valves, which a had back cut 20 degrees and I'm working the head ports just to see if it helps. The Question I have is the intake part of the head where the air will go past the guide in the pocket: The machine work is even on all 3 ports but my theory is if it can swirl past the guide it will run better. I think if it can swirl towards the center it will work better. But the design of the head is the same on each port. I can grind it to make that work but if it is better to open up both sides of the guides than I will do that. :?: