coolant in oil on 2003 Chevrolet Malibu

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
Just rebuilt engine- runs but rough shut it down.
coolant in oil
Heads were reconditioned, new gaskets, thermostat was replaced.
exhaust was light blue/steamy
Is this a cracked block or head
(1) Answer
Normally, this would point immediately to a head gasket leak. If that's not it, then it may be a problem with the heads or the block.