Box For 1996 Z71 Ext Cab

[samger2]

I did some searches but didn't come up with anything. I'm looking to potentially build a box for my 1996 Z71 ext cab that will go under the driver side portion of the rear seat. I'm looking to use either a 10 or a 12. My question is, has anyone built a box like the single downfiring one near the bottom of the page?

 

http://www.subthump.com/silverado.htm

 

In other words does anyone have the dimensions? I got in the truck and did a bit of measuring this weekend, but I'm not a whiz at box building and there are some curves and contours under the seat that I wouldn't want to mess up.

 

I suppose I could glass the bottom section...I've done that before, but I'm trying to avoid that since glassing is nasty work especially in 90 degree heat.

 

Thanks in advance.