If your port is 1.5" you should at least leave 1.5" of clearance from the back wall, so bad there, your port area should be no less that 10 square inches of port area per cubic foot of net volume so bad there also.
I didn't even look at the port measurements. I just looked at the box volume and port tuning freq. That said, if you tune high for max gain, you'll be in the 45 to 55Hz range, and the box will sound like really really loud garbage. It'll be very boomy with no bottom end at all. Unless you're building a box for SPL burping at pro events, which doesn't fit the dimensions of the above example, then tune the box around 28-31Hz, take the +3dB in gain you'll get, and be happy. A box with too much gain will not sound taht smooth transitioning to your mids, either.