Engine Run's Hot

I am in need of help with my 1995 Ford Probe GT V6 2.5L car. It has approx (I believe 154,000 miles on it) and its a great car.

Problem is this, the engine runs but it always runs hot quickly and when raced a bit, the exhaust puts out like a white "steam" type smoke.

I was told by my brother who knows a bit about cars that it might be either a cracked head gasket or a cracked head. I need to know exactly what it might be cause among that I've been told it was the CYLINDER head. I am so confused and just need to know down right. Which head is it?

I was also referred to put a new timing belt on and a thermostat as well. I know it need a new battery but like I said, I'm stuck with which head is the actual one that needs to be checked for cracks and which one doesn't. Please help me.

-- Dustin