Freeze plug leak????

I have a 1963 Dodge panel truck with a '86 318, 4 barrel that came out of a cop car and it is leaking anti freeze from what appears to be a 3/4" galley way that goes straight up into the block above the starter? Where does this go? Is one of the rear freeze plugs blown behind the bell housing(auto trans) and leaking out here? Any info would be great before I pull the engine. thanks.