Electric water pump BBL

Here is my problem. I have a 451 stroker and I have an Aluminum Radiator with a 17in Spahl fan. The car still over heats when idled around in the heat.
I do have also under drive pullies. If I was to install an Electric Water pump do you guys number one, Think it will keep the car cool? and two do you maintain the thermistat? any help would be great. I was thinking of going with the miezer electric water pump in Jegs.
Thanks again.

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