This is a technical tip for the cylinder baffling modifications we’ve come up with for the IO-360 and IO-375 engines. The windows in front cylinders #1 and #2 drop cylinder temperatures by approximately 30 degrees. They are placed over the deep fins below the mid-line of the cylinders which are approximately 2.0” wide. The windows allow cooling air to enter the fins on the lower front portions of the cylinders. They are 1” tall x 2” wide. Cylinder #1 is relatively easy to do since it is a flat laminate backed with aluminum baffle. A few extra rivets may need to be placed once the window is cut. Cylinder #2 is a bit more challenging since it is a double wall baffle with 5/8 -3/4” air space between. I accomplish this by cutting the windows in both aluminum pieces, then placing foam core between the aluminum pieces and bonding it with silicone. I sand the foam back approx 1/16” from the window opening edges after it is in place between the aluminum and coat the exposed foam inside the opening with high temp silicone (finger wipe). I haven’t tried it yet, but I think if the window in cylinder #2 was even wider on the front side say, 2” tall x 3” wide forming a funnel down to the 1” x 2” dimension on the aft piece, it would improve cooling since I didn’t see as much temperature lowering on the #2 cylinder window as we did on the #1 cylinder window. (20° vs. 30°).