It seems your box is tuned to about 40Hz, and your cabinet volume is about 1.7 cubic feet. This is pretty small for a vented box, so you may have a hard time getting a subwoofer that will play nicely in this box.
According to the P-E Woofer Selection Guide, the Goldwood GW-12PC-4 would do pretty well in a vented box this size. It would give you and f3 a little above 40Hz, which should allow your port to give a boost where it is needed. It should handle the power output of this amp very well too.
Another option would be to plug your port. Generally sealed subs can get away with less box volume than a ported one, so this may open up some possibilities. Sealed box subs are generally more accurate and musical than vented ones, but they generally lack a bit of low frequency extension. The Dayton Audio DCS305-4 would play well in this box sealed. It would give you an f3 right below 45 Hz, and would have no problem with this amp as far as impedance or power handling. A nicer, and more expensive option, would be the Peerless 835017 XXLS. It would do really nicely in this box, and with this amp. It would give you an f3 in the mid to low 40 Hz range.
If you are going to leave the box ported I would say give the Goldwood a try. If you are willing to seal the box, the Dayton would be a nice choice.
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