Rockford Fosgate P300-10 behind the seat of a 79 Silverado

[Orion88]

I was looking at getting this powered sub for my truck but I want to make sure it will fit before I buy it. I can't measure how much room I have behind the seat so I thought I'd ask you guys. The sub box is 9-3/4" deep at the bottom and 6-1/8" deep at the top. It is also 13-3/8" tall and 18-11/16" wide. So will this fit behind my bench seat of my 79 Silverado?

http://www.crutchfield.com/S-ry00SQU...h-P300-10.html