Port matching your intake manifold to your throttle body is one of the cheapest and easiest ways to improve air flow in your air intake system; if you have the tools of course. Slapping a bigger throttle body onto an intake manifold that has a smaller opening results in there being a small lip that the air will come in contact with before flowing into the plenum. This is not ideal.
Also, the Skunk2 cast manifolds have a small casting lip that is a few inches past the plenum opening. We call this the "Speed Bump."
Our solution to the lip and speed bump problem is to match up and trace a thermal gasket that is the size of the throttle body we would like to install on the manifold. In this case we are installing a 74mm throttle body so we used a 74mm thermal gasket.
We then use a right angle die grinder with a tungsten carbide bit to remove the lip and contour the new opening so the air will flow smoothly into the plenum. We then do the same to the Speed Bump.
Now that the opening on the intake manifold matches the size of the throttle body, we move onto the finishing stages of smoothing it out with a sanding bit to allow the air to glide across the newly ported surface.
That's looking so much better. Notice that the Speed Bump has been completely removed and polished allowing for optimal airflow within the intake manifold plenum.
Note: The sharpie marks you see in the photo above are just on the thermal gasket from when we traced it earlier.
And finally here is our finished product with the thermal gasket and 74mm throttle body installed.
Yes this is a fairly straightforward process, but it is easy to make irreparable mistakes. It is also expensive to gather the necessary tools for the job. We're planning to offer this as a service available only on www.valexracing.com