It's going to be very difficult to get the lid to seal well this way, and will require some skilled carpentry and additional weatherstripping in the back. It would be much easier to build a short collar that goes all the way around.
I'm trying to find some porn filmed by a dog wearing a GoPro. - SharonaZamboni
Hunter, when you get bored, will you put a taco in my elephant's hands for me? - Hat