I am sure you folks will give me more ideas on what is going on with this issue. I have replaced the entire cooling system on this 440 and added two 12" electric fans in conjunction with the regular fan and new fan clutch, 180 thermostat, new high flow water pump, radiator was dipped and cleaned and I reflushed it 4 more times. No kinks in any hoses or any problems I can see and you can see the water pumping the fluid great.
I have been in the mechanic business for 25 years. That being said, I am always learning new things and if I don't know I will ask others for their ideas. I might be missing something here but I don't know what.
Now to fill you in with the big picture. Motor and heads rebuilt by a machine shop and has 800 miles on it at this time. Put everything back together and was noticing the temp on the higher side (not boiling). That is when I started changing the other parts that were not new like fan clutch, thermostat, waterpump and when that did not satisfy me I added the two 12" fans pushing through the radiator. I also flushed for the 4th time the motor and radiator when the waterpump was off and radiator hoses were disconnected.
I drove it 80 miles to go camping and it did alright, no boiling just on hot side of gauge. I drove up to 65 mph and it was climbing to the boiling point so I slowed back to 55 and it cooled back down. I sped back to 65 and temp climbed again so back to 55 and it cooled down again. I pulled over every time it started to get on the hot side and ran out with my laser thermometer to check the temp exactly. The hottest I could read was 225 at the top of the radiator and the rest of the radiator was below but around the same temp, so I know the radiator is not plugged.
I have read on the internet that some times newly rebuilt motors will run on the hot side until it is broke in all the way. I have never experienced this issue and I do not know if it is true, but I did read that on more than just one site. I have changed the break in oil after 500 miles with more break in oil. After 1000 miles total I will change to regular 10W30 oil and see if that will help but that does not seem like it would make it run cooler.
Am I missing something here that you can tell? You can read how much I have replaced and to me I can't see why it's running on the hot side.