Install the stencil on the factory rear engine cover. (Line the stencil up to the diagonal lines and bottom edge.) Tape the stencil in place. Drill out the small 23/64 holes, use a hole saw for the 2” and 2 ½” holes. Next clean up the holes by using a Dremel on the 2” and 2 ½” holes, oval out the smaller 2” hole.