Running hot

When filling the cooling system, did you bleed out the air pockets?

Im not sure they did all that at the shop but i will work on it now

Set the motor up while you can, make sure the carb is adjusted, and the timing is set.

Make sure the cooling system is actually full. Air pockets are unlikely on an old V8, but it could happen. Be sure your fan is bolted on the right way. Some fan blades can be reversed accidentally so they are blowing instead of sucking air in through the rad. (I speak from experience) How hot is it running? Some new engines run a little hot while they're new, but it its running way into the red on the gauge then that's a problem. Try running it without a thermostat. It's not like newer cars that have to have them to keep the electronics working properly. Don't leave it out indefinitely, but you can take it out to keep it running cooler while you tune and adjust it and it will also perhaps eliminate the thermostat as the source of the problem.

I have changed the radiator,water pump,thermostat,head gaskets. And it still keep running hot. What should I do next

Purge the cooling system from air pockets. Watch this video on how too... www.youtube.com/watch?v=zUpXgAJ1gjU