Greetings: I own a 91 2500. Couple of questions.

1. I have the standard AM/FM radio and would like to install a CD/AM/FM radio in the pocket area below the AC vents. I would like to pull and replace of the stock radio with either a drop in GPS system or a monitor that I could interface with a GPS system. Does anyone know of an aftermarket set up that would fit the bill.

2. Is the hole for the standard radio with its square shape called a “Double Din”

Thanks for any help.