Mech fan suggestions…..

I assume your rad is aluminum.
By any chance do you have a copper / brass in good (CLEAN TUBES) you could swap for testing?

Seems like some Al rads are pushed to the rear of the car by core thickness and mounting brakets.

Stock copper/brass can be 3 row with the extra row to the front.

You could open up the 22 inch rad support to accept a 26 in rad.

You could add high CFM pusher electric fans

High flow thrmostat, propper ratio pulleys, high flow water pump.

In all reality 200 to 210 is not all that hot.

220 is starting to push things.

Recently in another post i posted some radiator design info and they were talking that fins per inch was the most inportant aspect to a rad because ALL of the heat transfer from the tubes takes place at the point where the fin is soldered to the tube.

Good luck
I agree 200-210 isn't hot. 100%.

But here's the issue. There's no room for error. Idling in traffic because of a traffic jam. Moving up less than a car length every minute or so. In the middle of a hot summer day, which would otherwise be a nice day driving down the road.

There's no room for error. I used to think the same way. 200-210.......even 215-220 wasn't hot.

After my EXPERIENCE with this hot slant 6 in Vixen and what I did and was successful with combating the heat, I've changed my tune. I believe now, in real world performance engines, keeping them the coolest you can is best.

Then here comes the argument running too cool adds extra wear, etc. Then tune for it. It's all in the tune. That's what I did. It works. The trick to all this is not letting the engine ever get to "that point" where there's no room for error. Because if you do, there's gonna be an error. There always is.

I don't want my "normally 200-215" engine stuck idling in traffic. It won't be a happy camper long. A stock engine will run like that all day. A performance engine will continue to generate heat. It's their nature. With advanced timing curves that start the ignition process early and burn it a long time, that heat is in the engine. It'll build up at idle and low speed and has nowhere to go. It WILL overcome the cooling system, if your normal operating temperature is 200 plus. Why?

There's no room for error.