The 401 has not been rebuilt, it has roughly 120K on it, and runs just fine. Fires right up without skipping a beat! I will try checking the lower radiator hose just to be sure, although it is new as well. Im going to check on the passages through the fins of the radiator and condenser, as well as checking the timing and fuel mixture, and also the compression, as suggested.
Thank you all for the suggestions. It may be a week or so before I can get to everything, but I will touch back here afterwards to report on the findings.