My grill block and air dam is 13" tall. I cut off the remaining 11" and used ABS paste to attach it to the back of the original piece and then screwed it back onto my bumper. I had poured acetone on the two pieces, but it dried without doing anything. I had read people just dissolved ABS pieces in acetone to make their own paste and that definitely seems like what I bought, $4 for four ounces, and only covered about two square feet, but it is holding. Hopefully closing off the opening in the winter and making it more rigid will help measurably. When it gets warmer I need to cut a new opening, supposedly in front of the radiator, but when I use AC I am pretty sure that needs ventilation, too. I am going to try it with bell-mouthing this time and really need to get around to ducting.