Finished installing nutplate mounts and riventing angle brackets to plenum, then attacked marrying the inlet of the plenum to the cowl inlet. After exploring a few less labor intensive ideas, decided to stick to the original plan of laying up a contoured inlet guide on the plenum to match the cowl, then bridge the gap between them by either overlapping or with rubber strips like the bottom. Layed up 4 layers of glass strips over foam plugs covered in tyvek tape that models the cowl opening. Almost done with engine cooling!