1996 Pontiac Firebird Oil In Radiator

Yesterday while I was driving I noticed an sudden raise in my cars temp. She normally runs at a cool 140 and then all of a sudden it was at 180 this was very unusual so I brought her home and parked it. Then this morning I went to check the water level in the radiator and discovered a crap load of oil in the radiator so I know this is normally a sign of a blown head or a Head gasket but what I need to know is how do I find out what side is blown with out having to take off both heads and looking at them like that. and since there is so much oil in the radiator is the block still going to be ok? I mean it will start and run ok but I'm afraid that this oil in the coolant is going to screw the motor all up. is there anything I can do or should I replace the motor????
Thank you for your response
Tina