Cleaning water jackets 225

I am haveing the same problem with a 225 I put into my 82 dodge p/u stepside. I have done all the cures listed except the head gasket. The motor was bored .030 over. It was a " doner" from a newer van and I can assure you it was cleaned veeeeery well before the build. I live in southern Az. and heat is a major factor. I even went as far as to change out the radiator w/ a new one w/ air for more cooling. I installed a trany cooler out frount and disconnected it from the radiator. I also installed a mechanical gauge as the truck only had a light. A new hiflow water pump was instaled in a effort to help the problem. two things , beside the gasket I did not see; I tried to use a 1bbl. thinking that fuel mileage would improve, and have thought that at 4025. ft above sea level its just not able to flow enugh c.f.m. to keep the truck from running lean. I didnt see where you had set the timing, to much advance ( even hidden in a bad dist weight) may help to create heat. All the other people that said to test it with a infrared heat gun were correct!! Have you tried to move the sensor, mine was right up on frount of the head ( the hottest frickin spot)> One thing I did find that helped for a temp. effect was to use a additive, I.E. water wetter, blue ice ect. You can also run straight water and drain it out in the fall. Water moves heat better then antifreeze. Your temp test at the radiator top tank reveals a lot. you problem is in the motor. Hope you get it . If so , message me as now in the summer I have to drive a blue oval because my "baby gets hot" and not in a good way!!