foxbody 5.0 coolant leak resolution.

I have heard several people say in different places its possible to replace the heater core without pulling the dash through the glove compartment. Has anyone done this or can think of a way it would be possible? I was thinking of cuting the box of where you can see it in the dash. Any advice?

I have slow coolant leak on a 1987 Mustang GT, which has proved hard to locate. I do not have a pressure test unit personally, which might be the solution. The leak appears to be coming from the front of the engine, around the timing chain cover area. I can never see the leak while the car is...