the calc i use says i need to make it longer
i go to the12volt.com
"Calculators, Charts, Diagrams"
scroll down, click "Volume Calculator - Rectangular/Square Enclosures"
scroll up, its right above the box volume calc for the spuare enclosures
my port is 1.5"wide x 17.5"tall x 9"long
and i have 1.8 cubes