340 running hot

I once had a new water pump that the lower hose outlet was never stamped out. It was blocked completely with flashing 3 inches up inside. Played hell finding out why this new motor was running hot. Since then I look at everyone and have found some restricted with flash and one that only had a hole the size of a dime to get coolant through.
Correct. Always check a new water pump just like you would a cylinder head. This has happened to others. It doesnt take much of a restriction to cause a problem.