The existing wiring in the car has a round connector with 4 wires of the following wire colors: RED (fused) , GREEN, YELLOW, BLACK.
The Vintage Radio has 5 wires: RED, BLUE, BROWN, Black (~12AWG), BLACK (~18AWG)
I would assume the red goes to red (power)
Black (heavy) goes to Black, (Second black = ???)
and that the GREEN, YELLOW, BLUE, BROWN are speaker wires and that the speakers ground out their mounting locations?
Can anyone confirm this? Thanks!

