Hi i have a coupe deville 81 with the 368 engine.
And yesterday i noticed some steam coming out from the middle of the car, i noticed that was the coolant is leaking from somewhere, i have no idea since its not the radiator.
Any ideas?

What do you mean by "middle of the car" ? Basic rule of thumb, check the easiest things first. Check all the hoses, both radiator (top and bottom) and heater hoses. Check the waterneck connection on the manifold, you may have a bad gasket or just a loose bolt. Check to make sure all hose clamps are tight.

Brian

middle of the car is near the firewall. actually is dripping directly on top of the muffler pipe (sorry about my english.).
Is there any hose or bolts near there?