I've been looking into the same setup for my 51 chevy. I talked to Old Air Products about their system, and they said it's made for the home mechanic to install, so it shouldn't be too hard.
I'm not sure that it will adapt to 6 volt, I have a 12 volt system so I didn't ask about that.
The speaker grill option I think is made for trucks without a factory radio, there isn't room for both.
