1989 Pontiac Firebird 1989 Pontiac Firebird coolant leak/cr

I own a 1989 pontiac firebird, and when I replaced my themostat and flushed the cooloant I noticed that it is coming out of the rear of the motor by the where the transmission meets the motor. I cannot see any leaks in the freeze plugs or any lines but, also the stream that comes out is a large stream 1/8" to 1/4". It just doesnt make any sense that my block could freeze so fast and a crack could be that big too. I was told that it could be a leak by the fire wall but I cannot see anything. Please help me in figuring this out. This is the only car I have and I have a newborn daughter and a wife that needs dependable transportation.