What side is the heater core on for 5th gens? (ST184)

[qtfsniper]

Hey everyone, it's my first post (sorry it's a help thread, but I really do need help). I'm working on a 1991 GT, and need to replace the heater core. I have a repair manual but it doesn't say anything about the heater core, just the other components. Which side is the heater core on? I'm trying to remove as little of the dash as possible. (and also, what color is the casing on it?) It's my first time doing this, and all my friends say it's pretty easy on their trucks.