Do I need to seal the fan shroud to the radiator?

The reason I ask is because I don't believe it made much difference in engine temp when I took out my two row OE radiator, shroud, fan clutch and fan and went to a three row aluminum radiator with dual electric fans. Granted, it hasn't been as hot lately, but it sits around 190 - 195 on and 80 degree day. I am waiting for a really hot day to see what it does. I had it almost to 220 on a 100 degree day with my old set up.

Thanks for the compliments! Early this week the Coolflex hose and matching reservoir tank will arrive and it will really look nice.