I already had scoops on my hood when I bought the car but it didnt have the fresh air holes drilled. I just used the photos I found here for reference and drilled near the hood supports. I used a 4-1/8" hole saw for mine but it was a bit too big. The seal is in place and stays in but there is a bit of side to side play when the sheet metal is in the groove of the seal. If I could do it over, it would be 4".