A common problem on Velocities is the overheating of the two cylinders that sit closest to the firewall. Jerry and Brett did a lot of head scratching. In the end, they decided to install a turning vane in each of the engine air plenum channels. The object is to divert part of the airflow directly onto those cylinders.
We also want to keep the airflow reasonably clean, minimizing turbulence. To this end, we've made cuts on both sides of the plenum channel. We'll insert the turning vanes from outside the plenum.
We've cut narrow arcs on either side of the plenum channel. The photo on the left is an attempt to show the leading edge of the the cut above the point where the plenum begins to curve downward, toward the engine. In right photo, you can see that we've followed the curve parallel to the bottom of the the plenum.