[BOBOCobra]

I think you are overthinking this. It is pretty simple, more air and/or more water. If the issue is at idle you need to move more air for sure (bigger/more fans) and see what the temp difference is between the rad and the motor. If the rad is 190 and the motor is 220 (as an example) the issue is more water. Rather than change the crank pulley, make a smaller WP pulley and overdrive it. If the rad is not cool enough you need more air through it. your only choice is bigger and badder fans. get the air fixed first, then the water. If you get the air fixed and have a temp sensor and proper water flow the fans will shut off whenever they need to. Let the system do its job. as a general rule, I use 100 degrees over ambient as the max target temp in traffic driving for a BB motor in a confined space. it may go 105 over, but that is the range. ambient has an impact as well as bay circulation but get the proper air flow thru the rad, then look at the water and then let the system work.