I had a similar challenge with my BBC 56 Chevy.
Had a big B Cool rad, twin spalls fans and a shroud, panelled in the radiator so that all air coming in was ducted through the rad, bigger pulleys to make the water pump run slower to ensure thermal transfer to the water blah blah blah - still ran at 220.
Finally worked out that the hot air had no means of escaping as the headers and general Big Blockedness didn't allow for the required airflow.
Tested the theory by driving it with the hood off - trend setter as this was way before Roadkill - temperature dropped to 180 driving and 190 in traffic with both fans running.
Fixed it by louvering the inner wheel well panels and fitting a 2" cowl hood, open a the rear. The heat haze coming through the cowl was amazing and worked very well at stopping the windscreen misting up....
https://lh3.googleusercontent.com/KS...-no?authuser=0
https://lh3.googleusercontent.com/-G...-no?authuser=0
Plus try everything suggested, timing, running lean, etc. Nothing worse than a vehicle that overheats. Takes the pleasure right out of the drive.
P.
