hey bill great choice. i used to own one of those puppies, but i sold it to a friend, who is trying to sell it again. it should say in the specs how big to build the box. if the box is sealed it doesn't matter a whole lot. just make sure the box is sealed well, if i recall correctly they want .75 cuft internal air space with that sub. plus displacement i guess. i always forget how that works. but if you build the box to the spec sheet you should make out very well with that sub, i loved it. also i suggest a good amp, phoenix gold is what i ran it with.