Overheating issues with remanufactured 360

If you had used a heat gun you could have found out where the hotspot begins and worked from there. If one exhaust manifold is much hotter than the other, or one head is hotter than the other, or the temp at the top of the radiator is the same as the temp at the bottom, you would have some info to work with. A while back there was a thread where the op dismantled a newly assembled 340 completely because the timing chain cover seal had a squeak. You are rapidly falling into this trap. Next time get the book and do some research. Then...with extreme care build your own engine. With your dads knowledge I'm surprised you didn't do this from the start. Then you will know that some disgruntled employee didn't drop a marble into a water passage.