Flathead 6 running hot need HELP

I just bought this old trk,and we got it running just this week, after it had been sitting for a long time,the fellow I purchased the trk from, said the engine was rebuilt,with new water pump and everything,I believe him because it runs so good,and the water pump wasn't even painted,it has a 3 blade fan and thier was no thermostat,my radiator checked out good,I know nothing about these engines ,could someone pleas help

 

You need a thermostat, or at least a restrictor, knock the center out of the thermostat. Water is going through to fast to cool the motor.
Art

 

Thats what I'll do In the morning,man I appreciate the reply...