This very cool vehicle was in the process of a complete restoration to the factory style. The only exception was that the owner wanted a great audio system in it. The restriction was that none of it could be seen, so that the illusion of leaving the factory yesterday wouldn't be ruined. Definitely a challenge, but it came out sounding good enough to put a modern "factory premium" system to shame.
The engine room. That Optima battery was eventually covered with a replica old-style battery case, and all the amp wiring was covered in a matching braided loom to keep the theme.
This is what the factory dashboard looked like. As you can see, there's no place for a radio to go. A pair of speakers was eventually tucked up out of sight under each end of the dash.
This is the only part of the audio system you can see. A master volume knob was added in a factory hole. You'd never know it wasn't stock.
Since there's no place for a radio, the source for the sound system is an iPod dock connector cable. The cable can be tucked out of sight at shows. With an iPhone connected, you can even stream Pandora internet radio while you're going down the road. How's that for modern?
Since you don't want to drill any holes in a vehicle like this, a mounting platform for the amp was attached to the floor with silicone adhesive. The amp then got screwed into the platform.
This is probably the smallest speaker box I've ever seen. It mounts the rear speakers in an unused and hidden area behind the bench seat back for rear fill and bass response.