Another experience with electric fans... Bigchief, Harold and woven said the same thing to me as well.. Dump the electric, let the stock setup do the job. I had some bigger problems as well. In my case. the car would run at 220, hot days it would overheat in the 240-260 range (I'd shut it off to cool) when idle.
I picked these guys brains and they really helped out, so I followed their advice. I can probably pull all the threads on the forum I read, but the to sum it up:
1. Dump the electrics and take them out (blocks air flow).
2. Time vehicle properly.
3. Impellar spacing (this is big...)
The thing that surprised me the most, I had some crud building on the intake manifold, so cleaned it out.