Just to throw some more gas on the fire. I have the Weiand on 2511. Put there by Dennis Quella. Has the plate added to the impeller to improve circulation. Triple pass aluminum radiator. Have had the car for 16,000 miles. Live in central CA, hotter than the dickens in summer. Run the A/C, stop and go traffic. Temp is never above 220, never hisses, burps or gurgles.
Maybe - I have never pulled it off - there is a hole drilled for circulation. I don't know.
I think I understand the theory behind what George is saying, and it makes sense, but I can't see where the missing circulation path is causing any trouble at all in my real-world situation.
YMMV
Larry
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