With those measurements you get a box with a volume of 2.64cu'
What I would do is build the port in between the subs, it looks better than on the side, also you don't have to deal with the correction factor which will save you space in your small enclosure. The port would be 1.5" wide, 6" tall, and 8.25" long. This will get you right around 32Hz.
If you take the dimensions of the port, including the material to make it (3/4") it comes to .1cu'. The subs together need 2.2cu' so....
2.64 - (2.2 + .1) = .34 left for sub displacement. It may be more than you need, but that will only add air space to the box's volume...maybe tuning it a Hz lower.
If you want a drawing let me know.
2006 Jeep Liberty
Adire Audio 15" Brahma running off Cadence A7hc, Clarion hu, MB Quart 6.5s and 5.25s running off old school Punch 800a4
146+db @ 38hz with 1200w and a single 15"
Lv = [(14630000 x R^2) / (Fb^2 x Vb)] - 1.463R
*Vb = vol. in cu"
**R = sq.rt. A / Pi (for square/slot port)