I have a similar setup to yours including a higher output water pump, except that I have a stock 2 core copper radiator, 4 blade fan, and no shroud. When I bought the car it had an electric pusher fan. I saw the same symptoms you describe. The fan was on a switch so I could turn it off and on at will. I found that it had absolutely no effect. As my temps would creep up in city driving I could turn on the fan and they would just continue to creep up. So I took mine off. I'm with George in that I think it may have blocked airflow and made it worse.As purchased my 440 had stock heads & pistons. Since then I have made a few mods to bump up the compression and therefore more heat. The last machinist who worked on my engine is a Mopar guy and a serious drag racer. He suggested running a 160* thermostat. He said to try and run it just a little hotter than necessary to make sure the choke opens. He was working on my engine because I had a detonation issue. Stock C.I. 440 heads are prone to detonation due to the spark plug placement. So keeping the engine as cool as practical pays benefits in preventing detonation problems.When I put the engine back in the car with the new 160* stat it overheated right away. After a little trial and detective work I noticed that the new stat had an opening that was considerably smaller than my original 180* stat. So with the old 180* stat installed everything was back to normal. Note that this was just last month when we had a warm stretch of 40*-60* days. It still wanted to get a little warm in city driving. So before things get too hot this summer I'll be installing a 3 core aluminum radiator. As noted in a thread on radiators last week the best performing radiators have a fin count of 14 - 16 per inch. All of the folks in this forum who have gone this route have cured their overheating problem. You don't have to hit me in the head more than a few times for good advice to sink in. ;-)