Overheating problem continues

[82 GT]

I've been having trouble keeping my engine cool during long idles or in-town cruising. It gets as high as 220* during those time but cools back down to 180-190 on the highway.
I have a 4 core radiator that was recently hot-tanked at a repair shop so I know that's not the problem now.
I'm running a flex fan with a shroud, a 25/75 coolant/water mix and a 20oz bottle of REDLINE water-wetter.
I have a 180* thermostat and 13lb radiator cap.

Now, to add to the equation, I believe I might have a lean condition. I'm not positive yet.
Should I replace the cap & thermostat just for the sake of it?
Is it possible that my engine NEEDS an electric fan now or is it because I "might" have a lean condition?

I'm still running the stock fuel pump(maybe I'll have it ported and polished)..............private joke from another thread
I'm just kidding tireburner. I had to say that...