340 running hot

had an issue with the lower induction hose from the radiator to the engine , it would suck down together and resrtict the water flow though it . made a stainless steel one out of weldind rod put it in the lower hose , flow returned temp went down . another had a swimming head on a head gasket . compression leak cause overheating issues . and did you mag all the parts for cracks in the cooling system before building ?