i would try goin a lil bigger for ported. the website or the booklet that came with the sub should have the specs on sealed and ported boxes and i would run the recommended
i live in Greenfield which is like 15 miles east of downtown indy and i work for a car audio store and i build boxes for them ... hit me up on aim gcstud18
loudspeakers101.com/ventcal1 has a slot port calculator all u have to do is put in the internal cubes then desired tuning frequency the heighth and width of the port and it will tell you how deep to make the port