# Interesting Flow Pattern On 7K3 Heads



## PontiacJim (Dec 29, 2012)

We all know the benefits of porting and polishing, gasket matching, and even chamber work. In Jim Hand's book he shows these heads where he grinds inside the chamber to reduce the sharp contour/edge near the intake valve closet to the spark plug.

Here are the 1972 7K3 heads off my 25,000 mile 400CI engine. You can clearly see the smooth shiny area next to the intake valve while the rest of the chamber has a coating of carbon. It would seem to me that this shows the velocity of the intake charge and possibly where it is concentrated and where it must be slamming into the wall rather than making a smooth transition. This was apparent in all cylinders. I included a photo showing the opposite side of the intake as well which shows an even coating of carbon throughout. These heads will most likely be going on my 455CI build, but not until I do some chamber work. I believe this shape was designed for better fuel mixing, but it may be more of a restriction on high performance applications - at least my theory anyway.


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