After trimming out the hole for the oil cooler and sanding it to match pretty close to the shape of the oil cooler, I clamped it in place to drill the upper holes. The most difficult task for this section was to thread the screws into the plate nuts with only a Philips head screw driver. I ended up unclamping the oil cooler and assemble the screw a few times without the cooling duct, then re-installed the oil cooler on the duct once the threads were a little worked in.
