2 skar 15in evl

[mfull212803]

Needing some help building a box. The calculator I'm using isn't exactly what I'm looking for. I've got two skar evl 15s and a skar 4500 Amp. Looking at building a box for the back of a 03 tahoe. Widest it can be is 48in. Wanting to be around 8.5 to 10 cubic ft tuned to 32hz top firing with a center rear facing port I believe will get me where I want to be all input is appreciated for this noob.

[Joe X]

That's a lot of power to be oversizing the box to 4.25-5 cubes per sub.