super 1048 overheating

The title says it all.  even at idle, after about 20-25 minutes, the temp will climb to 215-220 and the cap will start to blow off.

Rebuilt 360 from older ford uhaul (never overheated in truck) with new hoses, water pump, no thermostat, new aluminum radiator and electric fans for push and pull.  Pull fan is Black magic fan moving around 3k cfm.

I had to offload by hand a few layers of sudangrass that got a little "soft" from the stem moisture (first time harvesting and a little learning curve) and while the wagon was sitting in the pasture with the fans moving it started blowing out, not a lot but noticed it and shut it down with fans still moving.

 

The previous engine I started the year with developed a leaky headgasket and would climb to 250 within a few minutes so that wouldn't work for anything but a paperweight.

 

I am at my wits end, the water pump is flowing, byurped the system and added a few more gallons of coolant after that find, new water pump and timing is correct.

Anyone have any ideas,  spring wheat straw is right around the corner and I need to get this back to reliable.

super 1048 overheating