Box design is for a 86 Monte Carlo SS. This was my first EVER design using sketchup, so not too much is to scale (main thing is the box is not that wide).
Box is 2.15 cubes net w/ 29.5 in^2 of port area; tuned to 31.5 Hz. Only question, is will that wedged-shaped portion on the rear of the box matter much, as far as airflow goes. You can see in the 3rd picture I'll have a 45 there to kind of round off that joint.
I really need that space to achieve the proper volume, and that design is getting the most from the box.