Any OE style chamber. Even the chamber used in the W-5 head is very sensitive to cutting the decks. In a perfect world, you would have a nice, clean .125 wide top cut all round the valve. As you start removing the material you start encroaching on the top cut. The closed chamber W-5 hated that and it's a ***** to correct once you do it. As your intake valve gets bigger, the effect is more noticeable.
That's why I don't like milling the open chamber head down to remove the open side. I've found once you get the quench pad below .060 deep (which is about .040 off depending on the castings) you start getting issues.
I was working with a guy who just thought getting rid of that side of the chamber was all that. So I went home an pd brought back two matching heads. One with the chamber milled the other not.
We didn't even measure flow. We just watched the manometer and listened to the flow. A deaf, dumb and blind kid could hear the difference.
After that, he gave up on that and found other ways to irritate me to no end.
Thanks very much for the detailed explanation. That is good to know. And the last sentence is most amusing LOLAny OE style chamber. Even the chamber used in the W-5 head is very sensitive to cutting the decks. In a perfect world, you would have a nice, clean .125 wide top cut all round the valve. As you start removing the material you start encroaching on the top cut. The closed chamber W-5 hated that and it's a ***** to correct once you do it. As your intake valve gets bigger, the effect is more noticeable.
That's why I don't like milling the open chamber head down to remove the open side. I've found once you get the quench pad below .060 deep (which is about .040 off depending on the castings) you start getting issues.
I was working with a guy who just thought getting rid of that side of the chamber was all that. So I went home an pd brought back two matching heads. One with the chamber milled the other not.
We didn't even measure flow. We just watched the manometer and listened to the flow. A deaf, dumb and blind kid could hear the difference.
After that, he gave up on that and found other ways to irritate me to no end.
