Here's the 22" Champion rad and fans I use in my 72 Demon (avatar) with the 408 (360-based). The fans/shroud cover it completely as you can see. I blocked off the little sections on the sides or anywhere else air could get pulled in without coming through the rad.
I've said it before - I drive it without issue on the street. Good example was the Woodward Dream Cruise (crawl?) last summer idling for about 30-40 min and went maybe 100 yds in that time in the 90 degree heat. Both fans were singing away...peaked at about 200 on the temp gauge. As soon as the traffic cleared and we could move, it dropped backed to its more normal 175-ish and I flipped off 1 fan which is how I usually run.
As others have said, you can get a prod system to work too. I didn't go that route and am happy with mine. Just showing you one system that seems to work.
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