1997 Pontiac Grand Am SE

This car needs a motor. The rest of the car is in good condition. If you have a 3.1L motor for this car you can put it in and have a good running vehicle. We bought it, thinking it was just intake gaskets. All that was done, but when we finished it appears that with the freeze plug gone in the motor that maybe it froze due to lack of anti-freeze. Once we put in the freeze plug within 10 mins the crankcase filled with coolant. so probably a cracked head? of block?