40 in wide
26 in. tall
22.5 deep
should equal about
38.5 W
24.5 T
21.0 D
or 11.46^3 Feet
Figure for about 1.46^3 ft displacement for the woofers and port and your dealing with about a 10^3 ft. enclosure.
To tune that to 35hz, do a verticle slot port on either side of the face of the box, extending towards the rear. use the internal hight as your max height dimention for the port, then add width to suit your area requirements. With those subs about 60^2 in. of area each is usualy good.
so the port should be about
24.5 in T
5 in W
15.3 in L
that gives you 122.5^2 in of port area.
funny me and keifersracing never talked, and though he didnt show any of his steps, we came up with the same exact number for port area ;-)