I've been hacking away at my cylinder plenums for several months to get all the CHT's balanced and within the green during cruise flight. I got to a point where my spread was pretty close but not real balanced between each bank of cylinders. This inspired me to start by making and installing a new set of forward cylinder baffles that are much more fitting for the engine. My idea was to trace the cylinder fins on a template and transfer it to a sheet of carbon I had made months ago. I then cut out the carbon, fit it to each plenum and floxed it in. Now, because the opening on each plenum is different, the entry volume delta is about 2.2sq in. This will obviously create a mis-balance between the cylinder banks, but this will also give me a good baseline to go off of. I will most likely have to slightly modify the left plenum to raise the temps a bit as it's opening is larger. This will, however be a much more attractive and fuctional way of tackling these temps.