Anywhere I can get a box built? Or find one?

I own a 1976 Type LT. I have replaced all the interior and added Sparco bucket seats but would like to replace the rear seat area with a custom built speaker enclosure. I am having trouble finding any where that deals with early model Camaros. Please Help!

I would say that's going to be a one-off deal. I'd say call any local install shop, or build it yourself are really going to be your only options.

You'll end up having to build one yourself or have a shop do it. If you are going to use a sealed box just build it yourself, very easy to design and make. Shops will usally charge you an arm and a leg for a custom box.