quote:Originally posted by George P:quote:
Originally posted by LTP:
What about the hump on the roof of the exhaust port? In a Mustang with headers does this help direct flow downward or should it be eliminated regardless of application?
The flat roof in the exhaust valve pocket and the bump in the exhaust port roof were placed there to encourage exhaust gases to flow downward into the exhaust manifolds. They should be beneficial for any exhaust system that turns abruptly downward to hug the side of the engine.
Just to add interest to that thought, I was told, rightly or wrongly, that the proper way to flow an exhaust port is with a stubby tube on it. It should be about 6" long and have a 3" radius. The tube is pointed directly down.
I seem to remember a Hot Rod magazine article/test where they attempted to verify the exhaust flow improvement with various configurations.
I don't know if the test was rigged but the best flow was with I just stated. They might have been BB Chevy heads? It doesn't seem logical that ALL heads would react the same way.
Just food for thought.